TiO 2 inorganic nanoparticle framework enhanced PEO based solid-state electrolytes for improved performance of solid-state lithium batteries

doi:10.21203/rs.3.rs-4136142/v1

Download PDF

Research Article

TiO 2 inorganic nanoparticle framework enhanced PEO based solid-state electrolytes for improved performance of solid-state lithium batteries

https://doi.org/10.21203/rs.3.rs-4136142/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Solid-state batteries with poly(ethylene oxide) (PEO) solid electrolytes are considered to have a wide range of application prospects. However, the high-level crystallinity of PEO leads to poor lithium-ion conduction capability, and there are problems such as poor electrochemical stability and undesirable contact characteristics of electrode/electrolyte interface in solid-state lithium batteries. In order to solve these problems, composite polymer electrolytes (CPE) containing TiO₂ as inorganic frameworks are prepared by a facile solution casting method in this paper. The results show that the CPE with TiO₂ content of 10 wt% elevates the conductivity to 1.08 × 10^− 3 S cm^− 1 at 60°C as one of the best polymer composite solid electrolytes. The Li symmetric battery with constant current charge/discharge cycle test at 0.2 mA˖cm^− 2 current density stabilizes the cycle for 129 h. The initial specific capacity of LiFePO₄/PLT10/Li at 0.1 C reaches 133.01 mAh˖g^− 1 with a coulombic efficiency of 83.44%. The discharge specific capacity remains 152.52 mAh˖g^− 1 with a cyclic retention of 109.51% for capacity after 20 cycles at 0.1 C. The oxidation/reduction peaks potential difference on the cyclic voltammetry curves (CV) is 0.483 V. As expected, the TiO₂ inorganic framework reduces the crystallinity of the PEO-based solid electrolytes and improves solid-state electrolyte and interfacial stability in Li-ion batteries, which bring higher coulombic efficiency and cycling capacity retention.

PEO

TiO2༛Composite solid electrolyte༛ Solid-state lithium batteries

Polymer solid-state electrolytes have great potentials as one of the most promising solid-state electrolytes. Polymer matrix and lithium salt are two parts of the polymer solid electrolyte. Polymer solid electrolyte has low-cost, low specific gravity, and processing facility^{[1, 2]}. However, polymer solid electrolytes are highly crystalline at room temperature and better ionic conductivity are needed for common polymer solid electrolytes such as Polyvinylidene fluoride (PVDF), Polyethylene oxide (PEO), Polyacrylonitrile (PAN), Polymethyl methacrylate (PMMA), etc.^[3]. PEO is an extensively applied high-performance polymer electrolyte in which lithium ions move through PEO by chain segment motion. According to the behavioral regularities of Li⁺ ion transport in PEO matrix, the integrity conductivity of Li⁺ ions is fairly regulated by the motion of amorphous phases among PEO composition. Poor lithium-ion conductivity through pure PEO (10^− 6~10^− 8 S˖cm^− 1 at 298K) is recognized its highly crystalline structure. Along with reduced mechanical strength and chemical stability while the temperatures raise, the lithium-ion conductivity of PEO will increase significantly. During the charge-discharge process, the volume of active materials in electrodes will change with irreversible deformation, leading to bad contact between electrode materials and solid electrolytes. Therefore, with the aim of solving the above dilemma, the preparation of composite polymer solid electrolyte (CPE) by directly adding inorganic filler to PEO-based solid-state electrolyte is an effective method^[4–7]. According to whether inorganic filler contains lithium ions or not, it can be divided into passive inorganic filler and active inorganic filler. Passive inorganic fillers are ceramic fillers that do not contain lithium ions, such as Al₂O₃^{[8, 9]}, SiO₂^[10], TiO₂^[11], ZnO^[12], ZrO₂^[13]_, while they scarcely have the ability to transport Li⁺ directly. Otherwise, active inorganic fillers are ceramic fillers with lithium ions in their bodies, such as Li₃N^[14], LiAlO₂^[15], Li_1.5Al_0.5Ge_1.5P₃O₁₂ (LAGP)^[16], Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP)^[17], Li_3xLa_2/3−xTiO₃(LLTO)^[18], Li₇La₃Zr₂O₁₂(LLZO)^[19], which present better electrical conductivity, chemical stability and wider electrochemical window. This series of materials can directly participate into the Li⁺ transport process. Zhai et al. prepared LATP/PEO flexible composite electrolyte with vertically aligned lithium-ion transportation channels in the substrate matrix, which exhibit an increasing conductivity from 3.8×10^− 8S˖cm^− 1 to 6.8×10^− 6 S˖cm^− 1 at room temperature^[20]. However, this is not sufficient for solid-state batteries. Gao et al. prepared CPE by injecting PEO and LLZTO electrolytes on PAN nanofiber network. Reduced crystallinity of PEO and improved the solubility of lithium salt was confirmed as a result of the introduction of inorganic ceramic filler LLZTO, which further improved the ion transport kinetics. The Li⁺ ion conductivity of CPE at 30°C was 2.57 × 10^− 4 S˖cm^− 1, with which the assembled LiFePO₄/CPE/Li cell can shuttle 100 times at 30°C^[21]. Passive inorganic fillers are less expensive and have a relatively simple synthesis process compared to active inorganic fillers. Meanwhile, the addition of inert inorganic fillers promotes the dissociation of lithium salts to release more Li⁺ through Lewis acid-base interactions^[22], and could enhance the amorphous phase in polymer matrix, block the polymer crystallization dynamics, reduce T_g, and finally improve the Li ion transport efficiency. Especially, inert inorganic fillers nanoparticles can provide more ion transfer paths on its nanoscale surface, which improves the electrical conductivity, tunes the mechanical properties of the electrolyte material, and inhibits dendritic growth of lithium. The significant increase of amorphous phase induced by inorganic nanoparticles would fill up the physical space which improve the interfacial contact between electrode/lithium metal and solid electrolytes, thus reduce the space for lithium dendrite growth^[23] .

TiO₂ possesses a unique electronic structure and controllable oxygen defects, which is considered a promising inorganic filler that interacts with lithium salt to regulate the dissociation energy of lithium ions^{[24, 25]}. Consequently, the effect of TiO₂ on the ion conductivity of LiClO₄ and NaClO₄ in polymer electrolytes has been studied carefully, but there is little research on its impact on LiTFSI in CPE^{[26, 27]}. On the other side, previous work has explored the composite polymer solid electrolyte with dual inorganic fillers, which significantly reduces crystallinity and improves lithium-ion conductivity. However, the two types of inorganic fillers increase dispersion difficulty and cost, which is not conducive to promotion and application. Therefore, it is necessary to use inexpensive, easily obtainable, and easily dispersed inorganic fillers as polymer solid electrolytes, and to deeply discuss their impact mechanisms on improving Li⁺ conductivity and electrochemical stability of PEO-LiTFSI-TiO₂ system. In this paper, TiO₂ nanoparticles is introduced into PEO with LiTFSI selected as the lithium salt to construct PLT (PEO-LiTFSI-TiO₂) system. The effect of TiO₂ as a nanoscale fillers and framework for polymer composite electrolyte in all solid-state Li-ion battery is further investigated by LiFePO₄/PLT_X(X = 0, 5, 10, 15 stands for 0%, 5%, 10%,15%TiO₂ in PLT)/Li coin-cell.

1.1 Pretreatment of Active Materials

PEO (M_v=600000), LiTFSI (purity > 99.9%,) and TiO₂ (particle size 100 nm) were dried in a vacuum oven at 50°C and 110°C for 24 h and then in a glove box for use. Anhydrous acetonitrile (99.9% concentration) was stored in the glove box. The used agents were all from Shanghai Aladdin Biochemical Technology Co., Ltd.. The content of water and oxygen in the glove box was controlled below 0.1 ppm.

1.2 Preparation of PEO based composite solid-state electrolytes with/without TiO₂

1g of polyethylene oxide (PEO) powder (MW = 600000) and 0.3258g of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) were weighed in a beaker at an EO:Li molecular ratio of 20:1. respectively, based on the total mass of PEO and LiTFSI, and then different ratios (0%, 5%, 10%, 15%) of nano-TiO₂ and 20 ml of anhydrous acetonitrile were added to the beaker. The mixture was stir red for 24 h on a heated magnetic mixer in a glove box at 200 rpm and 60°C to obtain a homogeneous electrolyte slurry. It was coated in the glove box on a PTFE template with a slot depth of 0.5 mm and a length and width of 10×5 cm, and placed naturally in the glove box for 24 h to obtain PEO-LiTFSI-TiO₂ films with different TiO₂ concentrations and a thickness of ~ 0.0165 cm, which were subsequently cut to discs with 16 mm diameter.

1.3 Assembly of solid-state battery

The solid-state battery was assembled into CR2025 coin cell in a glove box with atmosphere controlled and encapsulation pressure of 500 psi^[28] .

(1)LiFePO₄/PLTx/Li battery assembly sequence: anode shell - spring sheet - stainless steel sheet - lithium sheet - solid electrolyte film - LiFePO₄ cathode electrode - cathode shell^[29]. As shown in Fig. 1a.

(2)Li/PLTx/Li symmetric battery assembly sequence: anode shell - spring sheet - stainless steel sheet - lithium sheet - solid electrolyte film - lithium sheet - cathode shell. As shown in Fig. 1b.

(3)Stainless steel sheet (SS)/PLTx/SS battery assembly sequence: anode shell - spring sheet - stainless steel sheet - solid electrolyte film - stainless steel sheet - spring sheet - cathode shell^[30]. As shown in Fig. 1c.

1.4 Characterizations of PEO-based electrolyte and solid-state battery.

The XRD (X-ray diffraction) test was performed at Rigaku Smart Lab SE(Japan) with a sweep speed of 5°/min from 5 ~ 90° to determine the crystal atomic structure of the samples and to quantitatively analyze the composition of the composite electrolyte. X-rays obtained from Cu-K_α excited by electron beams at the voltage 40 kV and current 40 mA. The SEM (scanning electron microscope) was applied to observe the morphology at the microscopic level. EDS (Energy Dispersive X-Ray Spectroscopy) analyzes the elemental type and content of substances, allowing for rapid qualitative and quantitative analysis.

The AC impedance measurement was carried on an electrochemical workstation (CHI660E, Shanghai Chenhua Instruments Co., Ltd.). Assembled SS/PLT_X/SS symmetric cells were tested for AC impedance(EIS) using an electrochemical workstation with frequencies ranging from 0.01 to 1000000 Hz with the amplitude 5 mV and the bias current lower than 0.01 mA at 60°C; before testing, the assembled cells were left to stand at the test temperature for 2 h to maintain the stability of the system^[30]. The ionic conductivity of a solid-state electrolyte is given by Eq:

$${\delta }=\frac{\text{L}}{\text{R}\text{S}}$$

where δ represents the ionic conductivity (S˖cm^− 1), R the bulk resistance of the solid electrolyte (Ω), L the thickness of the solid electrolyte (cm), and S the apparent area of the electrode (cm²).

Constant current charge/discharge cycle tests were performed on Li/PLTx/Li symmetric battery with Shenzhen Neware battery testing system BTS4000. After holding at the test temperature for 2 h, the batteries were continued tested under 0.2 mA˖cm^− 2 constant current cycle, with each time charging 30 min then discharging 30 min. Overpotential vibration of the symmetric battery was observed in a certain period to study the electrochemical stability of the interface between solid electrolyte and lithium metal electrode^[30] .

Solid-state battery performance was characterized by assembled LiFePO₄/PLTx/Li battery with Shenzhen Neware battery testing system (BTS4000) charge/discharge cycle tests. The battery had to be rested at 60 ℃ for 24h before testing so as the polymer electrolyte slowly infiltrate into the void of the LiFePO₄ to provide the conductive network of Li-ions. The battery was then put in a chamber with 60°C constant temperature for constant current charge/discharge performance testing at 0.1 C from 2.8 to 3.65 V. For cyclic voltammetry test (CV), the CHI760E electrochemical workstation was used with voltage from 2.75 to 3.8 V and scanning speed of 0.1 mV/s at 60°C.

The XRD patterns of PEO and PEO composite solid electrolytes are shown in Fig. 2. The peaks at 19.3° and 23.4°(2θ) belonged to the features of PEO, while the peak intensity has a certain positive relationship with the crystallinity of PEO^[31]. The feature peaks of PEO are all detected in four composite electrolytes prepared. The intensity of these two diffraction peaks in PLT5, PLT10 and PLT15 is lower than PLT0, while the weakest peak intensity is found in PLT10. The peaks at 25.28°(2θ) belonged to the TiO₂ features, which was enhanced with the increase of filler concentration. Hence, the XRD analysis affirmed that TiO₂ could reduce the crystallinity of PEO-based polymer and increase the amorphous phase in the polymer matrix. The lowest crystallinity in PLT10 was achieved when the addition of TiO₂ was 10%wt.

Scanning electron microscopy (SEM) was applied to investigate the microscopic morphology and structural characteristics of the PEO composite electrolytes. Figure 3 shows the surface SEM images of PLT0, PLT5, PLT10 and PLT15. Compared with PLT5, PLT10 and PLT15, the microscopic morphology of PLT0 surface is relatively smooth and uniform. It can also be observed that the surfaces of PLT5, PLT10 and PLT15 are still relatively flat without obvious bumps. TiO₂ particles are uniformly dispersed in the PEO substrate without obvious aggregation.

Figure 4 displays the EDS plots of PLT0, PLT5, PLT10 and PLT15. The uniform elemental distribution of C, O and F in PLT0 indicated that the polymer is uniformly distributed. The uniform distribution of Ti in PLT5, PLT10 and PLT15 indicate no obvious agglomeration of TiO₂. The obviously changed distribution regions of C, O and F elements and the XRD test results suggest that the addition of TiO₂ could reduce the crystallinity of PEO-based polymers and increase their amorphous phases.

Figure 5 shows the EIS plots of SS/PLTx/SS cell at 60°C for an EO:Li molar ratio of 20:1. In general, the AC impedance curve of the polymer solid-state electrolyte consists of a semicircle arc at high frequency zone and an oblique line at low frequency zone while below the glass transition temperature. The intersection of the arc and the oblique line indicates the bulk resistance (R_b) of the solid-state electrolyte. While the ambient temperature raises to glass transition temperature, the AC impedance spectrum curves of the polymer solid state electrolyte transfer to only one oblique line. The intercept of the sloping line on the X-axis represents the bulk resistance (R_b)^[32]. As read from the graph, the bulk resistance (R_b) of PLT0, PLT5, PLT10 and PLT15 at 60°C are 20.4 Ω, 11.7 Ω, 7.58 Ω and 11.3 Ω, respectively. Their conductivity is calculated by the equations and shown in Table 1. The conductivity of the materials are all enhanced by the addition of TiO₂, and the highest conductivity of PLT10 with 10% TiO₂ reaches 1.08 × 10^− 3 S˖cm^− 1. The reason can be attributed to the addition of TiO₂, which accelerated the dissociation of lithium salts due to Lewis acid-base action and release of more free Li⁺. The addition of inert inorganic fillers could enhance the amorphous phase in the polymer matrix, block the polymer crystallization dynamics and reduce T_g, and finally improve the Li ion transport efficiency^[23] .

Table 1

Bulk resistance and conductivity of PLT_X composite solid electrolytes at 60°C.
Materials	bulk resistance(Ω)	conductivity(S˖cm^− 1)
PLT0	20.4	4.02×10^− 4
PLT5	11.7	7.01×10^− 4
PLT10	7.58	1.08×10^− 3
PLT15	11.3	7.26×10^− 4

Constant-current (0.2 mA˖cm^− 2, 60°C) charge-discharge cycling test results of symmetric Li/PLTx/Li battery is shown in Fig. 6, which could evaluate the contact efficiency and electrochemical stability of solid electrolyte towards Li metal. The polarization voltage ranges during cycling for PLT0, PLT5, PLT10 and PLT15 are 0.0815 ~ 0.0939 V, 0.037 ~ 0.059 V, 0.0421 ~ 0.066 V and 0.037 ~ 0.065 V, respectively. During the cycling process, the stable cycle time are 32 h, 100 h, 129 h, and 82 h, respectively. Obviously, the polarization voltage of the electrolytes decreases after the addition of TiO₂, and the cycle life increases in all samples. Related studies suggest that the decrease in polarization voltage may be due to the repeated lithium aggradation process by improving interfacial contact between electrolyte and lithium metal^[33]. Li⁺ transport behavior in the polymer electrolyte bulk phases could be regulated by TiO₂ nanoparticles fillers, which could yield homogenized lithium flux and played a certain inhibitory role on lithium dendrite generation. Further, it would improve the adhesion of CPE to the electrode, so as to reduce lithium dendrite growing space and the interfacial resistance caused by physical contact problems. Meanwhile, the TiO₂ nanoparticles could significantly enhance the mechanical strength of the PEO electrolytes, which can effectively resist the short circuit caused by the electrolyte penetration from lithium dendrite growth ^[23] .

To study the electrochemical/interfacial stability of the prepared electrolytes, LiFePO₄ is selected as the cathode material, PEO-based composite solid-state electrolyte PLT_X (X = 0%, 5%, 10%, 15%) as the electrolyte film, and lithium metal as the anode to assemble a solid-state lithium metal battery. The initial 0.1C charge/discharge curves and rate capability are measured at 60°C in the voltage range from 2.8 V to 3.65 V, which is shown in Fig. 7.

Figure 7a reveals the activation process during initial charge-discharge test of LiFePO₄/PLT_X /Li cells. The initial discharge capacities of PLT0, PLT5, PLT10 and PLT15 are 124.18, 106.53, 133.01 and 100.14 mAh˖g^− 1, respectively. As well as the first coulombic efficiency are 73.77%, 69.68%, 83.44% and 67.72%, respectively. The results show that TiO₂ addition (10 wt%) has improved the initial discharge capacity and coulombic efficiency. However, the capability of both PLT5 and PLT15 decline, which may be related to the effects of different TiO₂ nanoparticles contents on the charge transfer rate and Li⁺ diffusion efficiency of CPE.

The cycling performance is one of the important indicators of the electrochemical stability of Li-ion batteries. Figure 7b shows the for 0.1C cycling performance of LiFePO₄/PLT_X(X = 0%, 5%, 10%, 15%)/Li cells. The discharge specific capacities of PLT0, PLT5, PLT10 and PLT15 for cycle 1 were 137.68, 100.14, 139.27 and 100.57 mAh˖g^− 1, respectively. After 19 cycles, their discharge specific capacities decay to 140.95, 125.54, 152.52 and 112.18 mAh˖g^− 1 with their cyclic capacity retention rates 102.38%, 125.36%, 109.51% and 111.54%, respectively. The experimental results show that the cycling capacity retention of PLT5, PLT10 and PLT15 with TiO₂ addition was remarkably improved. Both the discharge specific capacity and cycling capacity retention of PLT10 were higher than PLT0, which may be due to the fact that different inorganic filler additions have different effects on the electrochemical stability between the CPE and the cathode. Therefore, the addition of appropriate amount of TiO₂ nanoparticles inorganic filler could improve the electrochemical stability of CPE to cathode material, which was profit to the migration efficiency of Li⁺.

The rate capabilities of LiFePO_4/PLT_X/Li battery under 0.1, 0.2, 0.5 and 1 C discharge rate conditions are shown in Fig. 7c. The discharge capacity and discharge rate suggest a negative correlation, and the discharge specific capacity indicates a stepwise decrease with increasing discharge rates. As the discharge current increases, the de/lithiation and migration process of Li⁺ is hindered due to increased polarization, resulting in a decrease in electrochemical performance. When the discharge rates increase to 0.2 C, 0.5 C and 1 C, the capacity retention are 93.20%, 84.47% and 100.47% for PLT0, respectively. The corresponding retention are 93.57%, 89.93% and 95.99% for PLT5, are 98.50%, 97.86% and 98.67% for PLT10, and are 103.99%, 99.40% and 97.80% for PLT15, respectively. After high current discharge of 1 C is done, the batteries are recharged-discharged at 0.1 C for 5 cycles. And the specific capacities of PLT0, PLT5, PLT10, and PLT15 are 144.72, 111.84, 150.10 and 137.84 mAh˖g^− 1, respectively. PLT10 has higher discharge capacity and capacity retainment rate compared with PLT0, which indicates that the addition of 10 wt% TiO₂ nanoparticles has a positive effect on promoting the lithium-ion migration.

To more precisely compare the electrochemical performance of PLT0, PLT5, PLT10 and PLT15 electrolytes, cyclic voltammetric tests were performed with a sweep rate of 0.1 mV/s with voltage ranging from 2.75 to 3.8 V. The CV curves obtained are shown in Fig. 8a below. The curve demonstrates the effect of adding TiO₂ nanoparticles on the cell kinetic performance. It can be observed that the redox peaks of four samples are within the potential range of 3.2–3.8 V. The oxidation and reduction peak potential are 3.798 and 3.239 V for PLT0, 3.799 and 3.26 V for PLT5, 3.73 and 3.247 V for PLT10, 3.8 and 3.25 V for PLT15, respectively. Based on the location of the reduction and oxidation peaks in the first sweeping cycle, the magnitude of the potential difference can be introduced as ΔE (ΔE = | E_pa - E_pc |, E_pa and E_pc are the oxidation peak potential and reduction peak potential on the cyclic voltammetric curve, respectively)^[34]. The ΔE of PLT0, PLT5, PLT10 and PLT15 are 0.559, 0.539, 0.483 and 0.550 V, respectively. PLT10 has the smallest ΔE among the four samples, which indicates decreased polarization of the electrode. Hence, the Li⁺ diffusion rate and the irreversible electrochemical reaction became faster and smaller after the appropriate amount of TiO₂ nanoparticles is added. At the same time, with the increase of TiO₂ nanoparticle concentration, the capacitive behavior appears in the CV curve of the battery, which is manifested by the broadening of the oxidation and reduction peaks, resulting in the increases of the specific capacity of batteries ^[35] .

In order to further investigate the mechanism for the electrochemical performance improvement of the composite electrolyte by adding TiO₂ nanoparticle, AC impedance spectrum (EIS) were conducted on PLT0, PLT5, PLT10 and PLT15, and the obtained EIS curves are shown in Fig. 8b. The EIS tests are taken at the end of activation when the SEI film has been formed on the surface of each electrode and ion and charge transfer resistance of the electrodes is better reflected. The semicircle in the high and middle frequency zones indicates the charge transfer impedance through the electrodes. The smaller radius implies the smaller impedance. The oblique line in the low frequency zone indicates the diffusion resistance of Li⁺, and the larger slope indicates smaller resistance. It can be observed that the radius of the arc of PLT10 in high frequency is smaller than PLT0, PLT5 and PLT15, and the slope of the sloping line of PLT10 in low frequency is larger than PLT0, PLT5 and PLT15. It means the charge transfer impedance of PLT10 and Li⁺ diffusion resistance of are the smallest among four samples. Finally, it can be concluded that the addition of appropriate amount of TiO₂ into PEO-based composite electrolyte could improve the charge transfer dynamics and Li⁺ diffusion efficiency.

Finally, the ionic conductivity and specific battery capacity of prepared composite electrolytes in this work are compared with some composite polymer solid-state electrolytes previously reported (Table 2). It can be clearly seen that the prepared PLT10 had excellent overall composite electrochemical properties compared to the previously reported CPE.

Table 2

Comparison of different composite polymer electrolytes.
Ingredient	Ionic conductivity (S˖cm^− 1)(60°C)	Capacity(mAh˖g^− 1) (0.1C, 60°C,LFP)	Ref
PPC/SiO₂	8.5×10^− 4	171	^[36]
PEO/SiO₂/Li₂SO₄ nanofibers	1.3 × 10^− 4	135	^[37]
PEO/ CeO₂	1.1×10^− 3	164	^[38]
PEO/SiO₂/UiO-66-NH₂/UiO-66-NH₂@SiO₂	8.1 × 10^− 6	119	^[39]
PEO/TiO₂	1.08×10^− 3	133.01	This work

In this work, PEO-based all solid electrolytes are prepared by a facile solution casting method, and further improved by the addition of nano-scale TiO₂ inorganic fillers. The 10% TiO₂ nanoparticles (PLT10) is found to be optimal under the condition of EO:Li ratio of 20:1, with the lowest crystallinity and highest conductivity of 1.08×10^− 3 S cm^− 1 at 60°C, one of the best polymer composite solid electrolytes. In a constant-current (0.2 mA˖cm^− 2 at 60°C) charge/discharge cycling test of Li symmetric battery, PLT10 is able to cycle stably for 129 h. Further, LiFePO₄/PLT10/Li batteries carry out a higher initial discharge specific capacity of 133.01 mAh˖g^− 1 at 60°C, showing a smaller potential difference (ΔE = 0.483 V), smaller charge transfer impedance and Li⁺ diffusion resistance than those of PLT0-based battery. The addition of 10 wt% TiO₂ nanoparticles can effectively regulate the crystallinity and ionic conductivity of PEO-based solid-state electrolytes, which could enhance the electrochemical/interfacial stability between the solid-state electrolyte and electrodes, and finally enhance the battery performance.

Funding:

This research was funded by Shandong Province Technology-based Small- and Medium-sized Enterprises Innovation Capacity Upgrading Project (Grant No. 2022ZDYF0201010); Doctoral Foundation of Guangxi University of Science and Technology (Grant No. 18Z13); National Key Research and Development Program of China (Grant No. 2022YFE0134600; 2021YFA0715404); Key Research and Development Program of GuangXi (Grant No. 2021AB05083).

Author Contribution

Author Contributions:Writing—original draft preparation,X.H.(Xiaoqi Huang);writing—review and editing,X.H.(Xiaoqi Huang),X.L.(Xuning Leng),T.L.(Tongsuai Li),C.W.(Chaojie Wang),J.T.(Jiacheng Tang) and L.X.(LiangXie);conceptualization,X.H.(Xiaoqi Huang);methodology,B.L.(Baosheng Liu);validation,X.H.(Xiaoqi Huang),C.W.(Chaojie Wang),J.T.(Jiacheng Tang) and L.X.(LiangXie);data curation,X.H.(Xiaoqi Huang) and X.L.(Xuning Leng);supervision,B.L.(Baosheng Liu) and S.Z.(Shaohui Zhang);funding acquisition, B.L.(Baosheng Liu) and S.Z.(Shaohui Zhang).All authors have read and agreed to the published version of the manuscript.

Zhou, Q.; Ma, J.; Dong, S. Intermolecular Chemistry in Solid Polymer Electrolytes for High-Energy-Density Lithium Batteries. Adv. Mater. 2019, 31, 1902029.
An, Y.; Han, X.; Liu, Y. Progress in Solid Polymer Electrolytes for Lithium-Ion Batteries and Beyond. Small. 2022, 3, 18.
Liang, J.; Luo, J.; Sun, Q. Recent Progress on Solid-State Hybrid Electrolytes for Solid-State Lithium Batteries. Energy. Storage. Mater. 2019, 21, 308–334.
Zhu, Z.; Hong, M.; Guo, D. All-Solid-State Lithium Organic Battery with Composite Polymer Electrolyte and Pillar[5]quinone Cathode. J. Am. Chem.Soc. 2014, 136, 16461–16464.
Lin, Y. C.; Cheng, J.H. Venkateswarlu M. Transport Properties of Nano-sized TiO₂-based Composite Polymer Electrolyte Prepared by a Green Method. J. Chin. Chem. 2012, 59, 1250–1257.
Lin, C. W.; Hung, C. L.; Venkateswarlu, M. Influence of TiO₂ nano-particles on the transport properties of composite polymer electrolyte for lithium-ion batteries. J. Power. Sources. 2005, 146, 397–401.
Srivastava, S.; Schaefer, J. L.; Yang, Z. 25th anniversary article: polymer-particle composites: phase stability and applications in electrochemical energy storage. Adv. Mater. 2014, 26, 201–234.
Lim, Y. J.; An, Y. H.; Jo, N. J. Polystyrene-Al₂O₃ composite solid polymer electrolyte for lithium secondary battery. Nanoscale. Res Lett. 2012, 7.
Suthanthiraraj, S. A.; Sheeba, D. J. Structural investigation on PEO-based polymer electrolytes dispersed with Al₂O₃ nanoparticles. lonics. 2017, 13, 447–50.
Gondaliya, N.; Kanchan, D. K.; Sharma, P. Dielectric And Conductivity In Silver-Poly (ethylene oxide) Solid Polymer Electrolytes Dispersed With SiO₂ Nanoparticles. A.I.P. 2010, 1313, 112–114.
Cao, J.; Wang, L.; He, X. In situ prepared nano-crystalline TiO₂–poly(methyl methacrylate) hybrid enhanced composite polymer electrolyte for Li-ion batteries. J. Mater. Chem. A. 2013, 1, 5955–5961.
Xiong, H. M.; Wang, Z.D.; Xie, D. P. Stable polymer electrolytes based on polyether-grafted ZnO nanoparticles for all-solid-state lithium batteries. J. Mater. Chem. 2016, 16, 1345–1349.
Kumar, B.; Scanlon, L. G. Polymer–ceramic composite electrolytes: conductivity and thermal history effects. Solid State Ionics. 1999, 124, 239–254.
Yang, J. X.; Yao, Z. X.; Jia, Y. Z. Study on the lithium solid electrolytes of Li₃N-Li₃Bi-LiCl ternarysystem – 2Li(3)Bi center dot 3LiCl lithium solid electrolyte. Solid State Ionics. 1997, 96, 215–218.
Villarreal, I.; Morales, E.; Acosta, J. L. Ionic conductivity and spectroscopic characterisation of γ-LiAlO₂-filled polymer electrolytes. D. Angew. Makromol. Chem. 19, 266, 24–29.
Meesala, Y.; Chen, C. Y.; Jena, A. All-Solid-State Li-Ion Battery Using Li_1.5Al_0.5Ge_1.5(PO₄)₃ As Electrolyte Without Polymer Interfacial Adhesion. J. Phys. Chem. C. 2018, 122.
Liu, L.; Chu, L.; Jiang, B. Li_1.4Al_0.4Ti_1.6(PO₄)₃ nanoparticle-reinforced solid polymer electrolytes for all-solid-state lithium batteries. Solid State Ionics. 2019, 331, 89–95.
Liu, W.; Lee, S. W.; Lin, D. Enhancing ionic conductivity in composite polymer electrolytes with well-aligned ceramicnanowires. Nat. Energy. 2017, 2, 17035.
Li, J.; Zhu, K.; Yao, Z. A promising composite solid electrolyte incorporating LLZO into PEO/PVDF matrix for all-solid-state lithium-ion batteries. Ionics. 2020, 26, 1101–1108.
Zhai, H. W.; Xu, P. Y.; Ning, M. Q. A Flexible Solid Composite Electrolyte with Vertically Aligned and Connected Ion-Conducting Nanoparticles for Lithium Batteries. Nano. Lett. 2017, 17, 3182–3187.
Gao, L.; Tang, B.; Jiang, H. Fiber-Reinforced Composite Polymer Electrolytes for Soli‐State Lithium Batteries. Adv. Sustain. Syst. 2022, 3, 6.
Feng, J. N.; Wang, L.; Chen, Y. J. PEO based polymer-ceramic hybrid solid electrolytes: a review. Nano. Converg. 2021, 8.
Yang, X.; Liu, J.; Pei, N. The Critical Role of Fillers in Composite Polymer Electrolytes for Lithium Battery. Nano-Micro. Lett. 2023, 15, 37.
Ni'mah, Y. L.; Cheng, M. Y.; Cheng, J. H. Solid-state polymer nanocomposite electrolyte of TiO₂/PEO/NaClO₄ for sodium ion batteries. J. Power. Sources. 2015, 278, 375–81.
Wang, X.; Hua, H. M.; Li, J. Y. Oxygen vacancies on surface of the TiO₂ fillers hinder Li⁺ conduction in PEO all-solid-state electrolyte. Ionics. 2022, 28, 85–97.
Luo, B.; Wang, W. G.; Wang, Q. Facilitating ionic conductivity and interfacial stability via oxygen vacancies-enriched TiO₂ microrods for composite polymer electrolytes. Chem. Eng. J l. 2023, 460.
Fang, R. Y.; Xu, B. Y.; Grundish, N. S. Li₂S₆-Integrated PEO-Based Polymer Electrolytes for All-Solid-State Lithium-Metal Batteries. Angew. Chem. Int. Edit. 2021, 60, 17701–6.
Doux, J.; Han, N.; Tan, D. Stack Pressure Considerations for Room-Temperature All‐Solid‐State Lithium Metal Batteries. Adv. Energy. Mater. 2020, 10.
Cui, Y. M.; Zhang, Z. H.; Huang, Y. Q. Electrode preparation and assembly method for all-solid-state lithium batteries. Energy. Storage. Sci. Tech. 2021, 10, 12.
Huang, X. Wu, L. B.; Huan, Z. Electrochemical test methods in the study of lithium ion solid electrolytes. Energy. Storage. Sci. Tech. 2020, 9, 22.
Li, X. L.; Wang, X. Y.; Shao, D. S. Preparation and performance of poly(ethylene oxide)-based composite solid electrolyte for all solid-state lithium batteries. J. Appl. Polym. Sci. 2019, 136.
Qiu, J. L. Study of poly(ethylene oxide)-based solid electrolytes and solid-state batteries. University of Chinese Academy of Sciences. 2020.
Dirican, M.; Yan, C.; Zhu, P.; Composite solid electrolytes for all-solid-state lithium batteries. Mat. Sci. Eng. R. 2019, 136, 27–46.
Zhang, Y. J.; Liu, B. S.; Li, F. Effect of doped NCA process on the performance of lithium-ion battery cathode. J. Guangxi. U. Sci. Tech. 2022, 33, 10.
Zhang, X. B.; Chen, M. H.; Zhang, X. G. Preparation of porous carbon nanofibers by electrostatic spinning and their electrochemical capacitive behavior. J. Phys. Chem. 2010, 12, 6.
Didwal, P.; Singhbabu, Y. N.; Verma, R. An advanced solid polymer electrolyte composed of poly(propylene carbonate) and mesoporous silica nanoparticles for use in all-solid-state lithium-ion batteries. Energy. Storage. Mater. 2021, 37, 476–490.
Yu, J.; Wang, C.; Li, S. Li⁺-Containing, Continuous Silica Nanofibers for High Li⁺ Conductivity in Composite Polymer Electrolyte. Small. 2019, 15.
Wang, A. X.; Tan, X. T.; Zhang, J. W. Nanocomposite with fast Li⁺ conducting percolation network: Solid polymer electrolyte with Li⁺ non-conducting filler - ScienceDirect. Nano Energy. 2021, 79.
Angulakshmi, N.; Zhou, Y.; Suriyakumar, S. Microporous Metal–Organic Framework (MOF)-Based Composite Polymer Electrolyte (CPE) Mitigating Lithium Dendrite Formation in All-Solid-State-Lithium Batteries. ACS. Omega. 2020, 5, 7885–7894.

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

TiO 2 inorganic nanoparticle framework enhanced PEO based solid-state electrolytes for improved performance of solid-state lithium batteries

Status:

Version 1

Abstract

Figures

INTRODUCTION

EXPERIMENTAL

RESULTS AND DISCUSSION

Conclusion

Declarations

Funding:

Author Contribution

References

Additional Declarations

Status:

Version 1