Research Article | Open Access
Qingya Guo, Fanglin Xu, Lin Shen, Shungui Deng, Zhiyan Wang, Mengqi Li, Xiayin Yao, "20 μm-Thick Li6.4La3Zr1.4Ta0.6O12-Based Flexible Solid Electrolytes for All-Solid-State Lithium Batteries", Energy Material Advances, vol. 2022, Article ID 9753506, 8 pages, 2022. https://doi.org/10.34133/2022/9753506
20 μm-Thick Li6.4La3Zr1.4Ta0.6O12-Based Flexible Solid Electrolytes for All-Solid-State Lithium Batteries
The doped garnet-type solid electrolytes are attracting great interest due to high ionic conductivity and excellent electrochemical stability against Li metal. However, the thick electrolyte layer and rigid nature as well as poor interfacial contact are huge obstacles for its application in all-solid-state lithium batteries. Herein, an ultrathin flexible Li6.4La3Zr1.4Ta0.6O12- (LLZTO-) based solid electrolyte with 90 wt% LLZTO content is realized through solvent-free procedure. The resultant 20 μm-thick LLZTO-based film exhibits ultrahigh ionic conductance of 41.21 mS at 30°C, excellent oxidation stability of 4.6 V, superior thermal stability and nonflammability. Moreover, the corresponding Li||Li symmetric cell can stable cycle for more than 2000 h with low overpotential at 0.1 mA cm-2 under 60°C. The assembled Li||LiFePO4 pouch cell with integrated electrolyte/cathode interface exhibits excellent rate performances and cycle performances with a capacity retention of 71.4% from 153 mAh g-1 to 109.2 mAh g-1 at 0.1 C over 500 cycles under 60°C. This work provides a promising strategy towards realizing ultrathin flexible solid electrolyte for high-performance all-solid-state lithium batteries.
Lithium-ion batteries are the dominant energy-storage devices due to high energy density, low self-discharge rate, and environmental friendliness. However, the energy density needs to be further improved in order to meet the increasing demands of electric vehicle. Substituting lithium metal for graphite anode is considered to be a promising strategy [1–5]. However, inferior cycling stability, lithium dendrite growth and safety risk hamper the developments of lithium metal batteries due to the use of organic liquid electrolytes [6–9].
To substantially overcome these issues, all-solid-state lithium batteries employing solid electrolytes, i.e., polymer electrolytes or inorganic ceramic electrolytes, attract increasing attention, which demonstrates conceivable potential for high-energy-density and safe lithium metal batteries [10–16]. However, due to the oxygen release from oxide cathode at high voltage, polymer electrolytes generally suffer from decomposition as well as deterioration of interface properties [17, 18]. While for inorganic solid electrolytes, the thick electrolyte layer, rigid nature and poor interfacial contact are the great challenges for their practical application [10, 19–21].
To prepare polymer-in-ceramic solid electrolyte is one of the most promising strategies for addressing abovementioned issues by introducing flexible polymer component while maintain excellent electrochemical stability, mechanical modulus and thermal stability of inorganic electrolytes [22–25]. Chen et al.  and Huo et al.  demonstrated μm polymer-in-ceramic solid electrolyte with 80 wt% garnet ceramics and~60 μm polymer-in-ceramic solid electrolyte with 80 vol% Li6.4La3Zr1.4Ta0.6O12 particles enabled by introducing PEO polymer matrix, respectively. PEO-based polymer matrix has been considered as a promising candidate due to excellent interfacial compatibility with Li anode . However, due to the inferior strength of PEO , polymer-in-ceramic garnet-based solid electrolyte show brittle fracture by reducing their thickness under high inorganic contents. Besides, traditional polymer-in-ceramic garnet-based solid electrolytes are often prepared by slurry casting method, which involves evaporation of massive noxious solvents [27, 30] and generally suffers sedimentation of agglomerated inorganic particles [31–33] during preparation process.
In this work, we develop a three-dimensional (3D) cross-linked conductive network for ultrathin and flexible Li6.4La3Zr1.4Ta0.6O12- (LLZTO-) based solid electrolyte with 90 wt% LLZTO content, featuring a thickness of 20 μm and ultrahigh ionic conductance of 41.21 mS at 30°C. Furthermore, integrated electrolyte/cathode interface is constructed through in situ shaping and curing the LLZTO-based film on the cathode surface, which would enable an intimate electrolyte/cathode contact. As a result, related Li||LiFePO4 pouch cell exhibits superior rate performances and cycling stability.
2. Materials and Methods
2.1. Material Preparation
Li6.4La3Zr1.4Ta0.6O12 (HF-Kejing), Bis(trifluoromethane) sulfonimide lithium (LiTFSI, 99.99%, Sigma-Aldrich) and LiFePO4 (Dynanonic) were dried in 100°C at vacuum oven for 12 h to remove moisture and stored in Ar glove box. Poly(ethylene glycol) diglycidyl ether (PEGDE, Mn of 500), diethylenetriamine (DETA) and poly(ethylene glycol) dimethyl ether (PEGDME, Mn of 250) were purchased from Aladdin. Li foils with a thickness of 50 μm were purchased from China Energy Lithium Co., Ltd.
2.2. Preparation of Solid Electrolyte Film
Firstly, PEGDE, PEGDME, DETA, LiTFSI and LLZTO were mixed without solvent, and a plasticine-like mixture was obtained after grinding for 2 h to ensure homogeneous mixture between large amount of LLZTO particles and a small amount of liquid precursor. In particular, 90 wt% LLZTO was involved with a molar ratio of 5 : 10 : 2 for PEGDE, PEGDME and DETA. And the ratio of EO:Li+ is 18 : 1. The as-prepared plasticine-like mixture was rolled out to be a LLZTO-based solid electrolyte prefilm with a controlled thickness at room temperature. Subsequently, the obtained solid electrolyte prefilm was cured in a 60°C vacuum oven for 1.5 h and then subjected to isostatic pressure (200 MPa) for 10 min at room temperature. Finally, the 3D ion conduction LLZTO-based film with a thickness of 20 μm was obtained after further curing at 60°C for 2 h.
2.3. Material Characterization
The crystal structure of the sample was characterized by X-ray diffraction analysis (XRD, D8 Advance, Bruker) with Cu Kα radiation of nm in the range of 10°-80°. Fourier transform infrared (FTIR) spectroscopy was collected on Netzsch X70. Thermogravimetric (TG) analysis was performed with Diamond TG/DTA at a heating rate of 10°C min-1 from 50 to 600°C under argon atmosphere. Morphologies of surface and cross-section were observed by field emission scanning electron microscope (FESEM, S-4800, Hitachi), and elemental distribution was analyzed by energy dispersive X-ray spectroscopy (EDS).
2.4. Electrochemical Measurements
Electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and direct-current polarization were carried out on Solartron electrochemical station 1470E to evaluate the ionic conductivity, electrochemical window and lithium-ion transference number of LLZTO-based film, respectively. The stainless steel (SS)|LLZTO-based film|SS cell was used to record the impedance spectra with a frequency range from 1 MHz to 10 Hz and potential amplitude of 10 mV. The ionic conductivity is calculated according to the equation of , where , , and are the thickness (cm) of the electrolyte, total resistance of the electrolyte (Ω), and the effective contact area (cm2) between SS electrodes and electrolyte, respectively. LSV curve was examined through SS|LLZTO-based film|Li at a sweep rate of 1 mV s-1 between 3 and 6 V at room temperature. The symmetric Li||Li cell was assembled to measure the alternating current impedance and direct current polarization with a 10 mV potential amplitude. The ionic transference number was derived by the equation of , where , , and is the initial current, steady current, initial charge-transfer resistances, and steady charge-transfer resistances, respectively. The ionic conductance of the electrolyte is defined as , where , , and represent the ionic conductivity of the electrolyte (S cm-1), the effective contact area (cm2) between SS electrodes and electrolyte during the evaluation of ionic conductivity and the thickness (cm) of the obtained electrolyte, respectively. The interface stability between electrolyte and metal lithium was assessed by EIS test using Li|LLZTO-based film|Li cell under different storage times at room temperature. Galvanostatic cycling of symmetric Li|LLZTO-based film|Li pouch cell with stripping and plating for 1 h was tested at a current density of 0.1 mA cm-2 under 60°C.
The LiFePO4, poly(vinylidene fluoride) (PVDF), LiTFSI and Super P with a mass ratio of 70 : 12 : 8 : 10 were coated on Al foil with N-methyl-2-pyrrolidone as solvent to prepare the composite cathode. The Li|LLZTO-based film|LiFePO4 pouch cell () was assembled to test the cyclic performance on LAND CT2001A battery system (Wuhan Rambo Testing Equipment Co, Ltd.) with galvanostatic charge and discharge between 2.6 and 3.9 V at 60°C. The mass loading of the active material LiFePO4 is ~3 mg cm-2, and the current rate is set as 1 mA g-1.
3. Results and Discussion
The synthesis procedure for the LLZTO-based solid electrolyte is shown in Figure 1(a). LLZTO powder, poly(ethylene glycol) diglycidyl ether (PEGDE), diethylenetriamine (DETA), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and poly(ethylene glycol) dimethyl ether (PEGDME) were mixed without solvent to produce plasticine-like mixture with high plasticity (shown in Video S1). Then, the as-prepared plasticine-like mixture was rolled out to be the prefilm through roll-to-roll process, which was subsequently subjected to two-step heat curing reaction and isostatic pressure to produce an ultrathin (20 μm) flexible 3D ion-conduction LLZTO-based film (Figure 1(b)), where the content of LLZTO reaches up to 90 wt%, leading to close packing of LLZTO particles for continuous lithium ion conduction. Besides, a robust 3D ion-conductive polymeric network is constructed through in situ heat curing reaction to generate another continuous conductive pathway among the LLZTO particles, while contributes to the strength and flexibility. The thin thickness and high ceramic content of the obtained LLZTO film is one of the best among the state-of-the-art oxide solid electrolyte thin films reported in the literature (Figure S1) [22, 25–27].
The employed garnet-type LLZTO powder with particles size of 5 ~ 10 μm exhibits cubic phase structure (Figure S2). Epoxy resin PEGDE composes of PEO-based main chain and two oxirane groups, and generates robust 3D polymeric framework by heat curing reaction with curing agent DETA. As shown in Figure S3, the band at 912 cm-1 assigned to characteristic peak of epoxy group in PEGDE and the band of 3270 cm-1-3360 cm-1 attributed to the vibration of N-H in DETA disappear after heat treating, indicating the reaction occurs between epoxy groups and N-H. The optical image further confirms the curing reaction of epoxy resin PEGDE (Figure S4). It should be noted that the optimized two-step heat curing reaction and isostatic pressure delivers compact stack of LLZTO particles (Figures 1(c) and 1(d)) and ensure complete cross-linked reaction between DETA and PEGDE. Close packing of LLZTO particles and 3D cross-linked polymer network with excellent mechanical properties contribute to achieve ultrathin LLZTO-based film. EDS mappings of the element C and La, derived from polymer components and LLZTO particles, demonstrate the uniform distribution of LLZTO throughout the polymeric framework (Figures 1(e) and 1(f)). As a comparison, the LLZTO particles are in looser contact by one-step heat curing reaction without isostatic pressure (Figure S5). Moreover, PEGDME is introduced to improve the interface compatibility between LLZTO and epoxy thermoset resin and connect the PEO-based and LLZTO ion conductive pathways. In addition, the garnet structure is sustained in LLZTO-based film after curing reaction of epoxy resin of PEGDE (Figure S6).
Benefiting from 3D ion conductive network, LLZTO-based film presents considerable ionic conductivity of S cm-1 at 30°C, and the calculated activation energy is 0.31 eV (Figure 2(a)). The ionic conductivities and corresponding Nyquist plots of the LLZTO-based film at different temperatures are shown in Table S1 and Figure S7, respectively. Compared with the ionic conductivity, the ionic conductance can better determine the ion transport capacity for the ultrathin electrolytes [34, 35]. The obtained 20 μm thick LLZTO-based film exhibits ultrahigh ionic conductance of 41.21 mS at 30°C. The LSV curve of the obtained LLZTO-based film was measured by Li|LLZTO-based film|SS cell, showing a wide electrochemical window of about 4.6 V (Figure 2(b)) and indicating potential applications in all-solid-state lithium metal batteries with various cathode materials. The lithium transference number (Li+), reflecting the situation of lithium ion diffusion in the LLZTO-based film, was calculated to be as high as 0.81 (Figure 2(c)), contributing to homogeneous Li deposition . The wide electrochemical window and high (Li+) can be attributed to the introduced high content single-ion conductor LLZTO ceramics , possessing excellent oxidative stability  and increasing the oxidative decomposition potential of the polymer component by dipole-dipole interactions  as well as immobilizing partial TFSI- anions through Lewis acid-base interaction . In addition, the time evolution of the impedance spectra of the Li|LLZTO-based film|Li symmetric cell is monitored at room temperature (Figure 2(d)). Neither the bulk () nor interfacial impedance () increases significantly over time, indicating LLZTO-based film has excellent interface stability against Li metal. The TG curves of LLZTO-based film and commercial PP separator have been shown in Figure 2(e). Compared with commercial PP separator, LLZTO-based film exhibits outstanding thermal stability with weight retention of 88.87 wt% up to 600°C. Combining the weight loss of pristine commercial LLZTO particles (Figure S8), the LLZTO content in the film is up to 90 wt%. Moreover, Figure 2(f) shows combustion experiments of the LLZTO-based film and commercial PP separator. Once commercial PP separator is subjected to flame, it shrinks and turns into ashes instantly due to poor thermal stability. In contrast, LLZTO-based film with high-content nonflammability LLZTO demonstrates excellent flame resistance. Although the polymer component of LLZTO-based film disappears, the LLZTO framework still maintains the structure integrity during the combustion test, indicating that LLZTO-based film would effectively depress the risk of thermal runaway and promote the safety of lithium batteries.
The cyclic performance of Li|LLZTO-based film|Li symmetric cell is evaluated, exhibiting cycling stability for more than 2000 h with a low overpotential of 10 mV at 0.1 mA cm-2 (Figure 3(a)). The stable overpotential during cycling further indicates the excellent interfacial compatibility between Li metal and LLZTO-based film. The slight overpotential fluctuations mainly originate from measurement temperature fluctuation due to uncontrollable external factors. Moreover, the Li|LLZTO-based film|Li symmetric cell only shows a slightly increased impedance during cycling (Figure S9), indicating the cell does not suffer from a short circuit [40, 41]. Figure S10 further displays SEM images of uncycled Li anode and cycled Li anode, respectively. No obvious defects or dendrites can be observed, demonstrating the uniform Li deposition during cycles. In order to verify the feasibility of LLZTO-based film in all-solid-state lithium metal battery, the commercial orthorhombic olivine structure LiFePO4 with a particle size of about 1.0 μm is selected as the cathode (Figure S11 and Figure S12) and Li|LLZTO-based film|LiFePO4 cell with integrated electrolyte/cathode interface is assembled. Figure 3(b) shows the cyclic performance of Li|LLZTO-based film|LiFePO4 cell at 0.1 C. The initial discharge specific capacity is 153 mAh g-1. The dip in the first 100 cycles is due to sluggish activation process . After 500 cycles, a discharge specific capacity of 109.2 mAh g-1 is obtained with a Coulombic efficiency of 99.88% and capacity retention rate of 71.4%, indicating the excellent cycling stability of Li|LLZTO-based film|LiFePO4 cell during long-term charge and discharge process, which can be attributed to excellent interfacial compatibility between Li anode and LLZTO-based film as well as intimate electrolyte/cathode contact enabled by in situ strategy . The corresponding charge-discharge curves are shown in Figure 3(c). Figure 3(d) further exhibits the discharge specific capacities of LLZTO-based film at different current densities. The discharge capacities of Li|LLZTO-based film|LiFePO4 cell reach to 151.1 and 150.4 mA h g-1 at 0.1 and 0.2 C, respectively. When the current density increases to 0.5 C, the discharge capacity decreases slightly to 142.4 mA h g-1. Even though current density is promoted to 1 C, Li|LLZTO-based film|LiFePO4 cell still delivers discharge capacity of 101.8 mAh g-1. More importantly, the capacity can maintain at 147.5 mAh g-1 with negligible loss when current density is reset to 0.1 C, proving excellent rate capability of the cell. These results clearly demonstrate the feasibility of LLZTO-based film in all-solid-state lithium metal batteries, and the obtained ultrathin LLZTO-based film is anticipated to achieve all-solid-state lithium batteries with high energy density via further matching high-loading cathode with unique structure design [44, 45]. In addition, the Li|LLZTO-based film|LiFePO4 pouch cell can continuously light the LED device when the cell is bent, folded and even cut (Figure 3(e)), demonstrating the excellent flexibility and safety of the LLZTO-based pouch cell.
In summary, a 20 μm-thick flexible LLZTO-based film is successfully prepared by solvent-free procedure. The content of LLZTO powder in LLZTO-based film reaches up to 90 wt%. The LLZTO-based film exhibits an ultrahigh ionic conductance of 41.21 mS at 30°C, superior thermal stability, nonflammability and wide electrochemical window as well as high lithium transference number of 0.81. Meanwhile, the Li|LLZTO-based film|Li symmetric cell can stably cycle over 2000 h at 0.1 mA cm-2. The assembled Li|LLZTO-based film|LiFePO4 cell with integrated electrolyte/cathode design demonstrates stable cyclic performance, showing a capacity retention of 71.4% after 500 cycles at 0.1 C. Moreover, the LLZTO-based pouch cell delivers excellent flexibility and safety. The presented ultrathin LLZTO-based film has great potential for practical applications in all-solid-state lithium batteries.
All data presented in the paper and the supporting information are available from the corresponding author upon reasonable request.
Conflicts of Interest
The authors declare no conflicts of interest.
Q.Y.G., F.L.X., and L.S. contributed equally to this work. Q.Y.G., F.L.X., and L.S. performed the experiments, analyzed the data, and wrote the initial draft. S.G.D., Z.Y.W., and M.Q.L. provided the assistance on the data collection and figure presentation. X.Y.Y. proposed and supervised the project. Qingya Guo, Fanglin Xu, and Lin Shen contributed equally to this work.
The work was supported by the National Key R&D Program of China (Grant no. 2018YFB0905400), National Natural Science Foundation of China (Grant nos. U1964205, U21A2075, 51872303, and 51902321), Ningbo S&T Innovation 2025 Major Special Programme (Grant Nos. 2019B10044, 2021Z122), Zhejiang Provincial Key R&D Program of China (Grant No. 2022C01072), and Youth Innovation Promotion Association CAS (Y2021080).
Figure S1: comparison of the thickness and ceramic content of reported oxide solid electrolyte thin film. Figure S2: (a) SEM image of LLZTO particle. (b) XRD pattern of LLZTO particle. Figure S3: FTIR spectra of PEGDE, DETA and cured PEGDE epoxy resin. Figure S4: the optical image of the mixture of PEGDE and DETA before and after heat curing. Figure S5: (a) top-view SEM image of LLZTO-based film without isostatic pressure. (b) Cross-sectional SEM image and (c) the corresponding EDS mapping of La element of LLZTO film without isostatic pressure. Figure S6: XRD patterns of PEGDE and LLZTO-based film. Figure S7: Nyquist plots of LLZTO-based film at different temperatures. Figure S8: TG curve of pristine commercial LLZTO particles. Figure S9: electrochemical impedance spectroscopy (EIS) of Li|LLZTO-based film|Li symmetric cell before cycling and after 20, 50, and 100 cycles at 0.1 mA cm-2 under 60°C. Figure S10: top-surface SEM images of (a) uncycled Li anode and (b) cycled Li anode recovered from Li|LLZTO-based film|Li symmetric cell after 100 cycles at 0.1 mA cm-2. Figure S11: XRD pattern of the LiFePO4 cathode. Figure S12: (a) SEM image of the LiFePO4 cathode and (b) the corresponding statistical size distribution. Table S1: the ionic conductivities of the LLZTO-based film at different temperatures (Supplementary File) Video S1: the video of the produced plasticine-like mixture through grinding LLZTO, PEGDE, DETA, LiTFSI, and PEGDME (Video S1). (Supplementary Materials)
- J. H. Wu, L. Shen, Z. H. Zhang et al., “All-solid-state lithium batteries with sulfide electrolytes and oxide cathodes,” Electrochemical Energy Reviews, vol. 4, no. 1, pp. 101–135, 2021.
- D. Lin, Y. Liu, and Y. Cui, “Reviving the lithium metal anode for high-energy batteries,” Nature Nanotechnology, vol. 12, no. 3, pp. 194–206, 2017.
- A. Manthiram, X. Yu, and S. Wang, “Lithium battery chemistries enabled by solid-state electrolytes,” Nature Reviews Materials, vol. 2, no. 4, p. 16103, 2017.
- M. Armand and J. M. Tarascon, “Building better batteries,” Nature, vol. 451, no. 7179, pp. 652–657, 2008.
- B. Q. Li, X. R. Chen, X. Chen et al., “Favorable lithium nucleation on lithiophilic framework porphyrin for dendrite-free lithium metal anodes,” Energy Material Advances, vol. 2019, article 4608940, 11 pages, 2019.
- J. M. Tarascon and M. Armand, “Issues and challenges facing rechargeable lithium batteries,” Nature, vol. 414, no. 6861, pp. 359–367, 2001.
- Y. Gao, Z. Yan, J. L. Gray et al., “Polymer-inorganic solid-electrolyte interphase for stable lithium metal batteries under lean electrolyte conditions,” Nature Materials, vol. 18, no. 4, pp. 384–389, 2019.
- Y. Wang and W.-H. Zhong, “Development of electrolytes towards achieving safe and high-performance energy-storage devices: a review,” ChemElectroChem, vol. 2, pp. 22–36, 2015.
- S. Y. Kim and J. Li, “Porous mixed ionic electronic conductor interlayers for solid-state batteries,” Energy Material Advances, vol. 2021, article 1519569, pp. 1–15, 2021.
- N. Zhao, W. Khokhar, Z. Bi et al., “Solid garnet batteries,” Joule, vol. 3, no. 5, pp. 1190–1199, 2019.
- Y. Jin, K. Liu, J. Lang et al., “High-energy-density solid-electrolyte-based liquid Li-S and Li-Se batteries,” Joule, vol. 4, no. 1, pp. 262–274, 2020.
- S. Xia, X. Wu, Z. Zhang, Y. Cui, and W. Liu, “Practical challenges and future perspectives of all-solid-state lithium-metal batteries,” Chem, vol. 5, no. 4, pp. 753–785, 2019.
- Y. Shen, Y. Zhang, S. Han, J. Wang, Z. Peng, and L. Chen, “Unlocking the energy capabilities of lithium metal electrode with solid-state electrolytes,” Joule, vol. 2, no. 9, pp. 1674–1689, 2018.
- R. Chen, Q. Li, X. Yu, L. Chen, and H. Li, “Approaching practically accessible solid-state batteries: stability issues related to solid electrolytes and interfaces,” Chemical Reviews, vol. 120, pp. 6820–6877, 2019.
- L.-Z. Fan, H. He, and C.-W. Nan, “Tailoring inorganic-polymer composites for the mass production of solid- state batteries,” Nature Reviews Materials, vol. 6, no. 11, pp. 1003–1019, 2021.
- H. Gao, N. S. Grundish, Y. Zhao, A. Zhou, and J. B. Goodenough, “Formation of stable interphase of polymer-in-salt electrolyte in all-solid-state lithium batteries,” Energy Material Advances, vol. 2021, article 1932952, pp. 1–10, 2021.
- J. Qiu, X. Liu, R. Chen et al., “Enabling stable cycling of 4.2 V high-voltage all-solid-state batteries with PEO-based solid electrolyte,” Advanced Functional Materials, vol. 30, no. 22, article 1909392, 2020.
- K. Nie, X. Wang, J. Qiu et al., “Increasing poly(ethylene oxide) stability to 4.5 V by surface coating of the cathode,” ACS Energy Letters, vol. 5, no. 3, pp. 826–832, 2020.
- J. Zhu, X. Li, C. Wu et al., “A multilayer ceramic electrolyte for all-solid-state Li batteries,” Angewandte Chemie (International Ed. in English), vol. 60, no. 7, pp. 3781–3790, 2021.
- X. Zhang, T. Liu, S. Zhang et al., “Synergistic coupling between Li6.75La3Zr1.75Ta0.25O12and poly(vinylidene fluoride) induces high ionic conductivity, mechanical strength, and thermal stability of solid composite electrolytes,” Journal of the American Chemical Society, vol. 139, no. 39, pp. 13779–13785, 2017.
- T. Deng, X. Ji, Y. Zhao et al., “Tuning the anode-electrolyte interface chemistry for garnet-based solid-state Li metal batteries,” Advanced Materials, vol. 32, no. 23, article e2000030, 2020.
- M. J. Palmer, S. Kalnaus, M. B. Dixit et al., “A three-dimensional interconnected polymer/ceramic composite as a thin film solid electrolyte,” Energy Storage Materials, vol. 26, pp. 242–249, 2020.
- W. P. Chen, H. Duan, J. L. Shi et al., “Bridging interparticle Li+ conduction in a soft ceramic oxide electrolyte,” Journal of the American Chemical Society, vol. 143, no. 15, pp. 5717–5726, 2021.
- Y. Li, X. Wang, H. Zhou et al., “Thin solid electrolyte layers enabled by nanoscopic polymer binding,” ACS Energy Letters, vol. 5, no. 3, pp. 955–961, 2020.
- T. Jiang, P. He, G. Wang, Y. Shen, C. W. Nan, and L. Z. Fan, “Solvent-free synthesis of thin, flexible, nonflammable garnet-based composite solid electrolyte for all-solid-state lithium batteries,” Advanced Energy Materials, vol. 10, no. 12, p. 1903376, 2020.
- L. Chen, Y. Li, S.-P. Li, L.-Z. Fan, C.-W. Nan, and J. B. Goodenough, “PEO/garnet composite electrolytes for solid-state lithium batteries: From "ceramic-in-polymer" to "polymer-in-ceramic",” Nano Energy, vol. 46, pp. 176–184, 2018.
- H. Huo, Y. Chen, J. Luo, X. Yang, X. Guo, and X. Sun, “Rational design of hierarchical “ceramic-in-polymer” and “polymer-in-ceramic” electrolytes for dendrite-free solid-state batteries,” Advanced Energy Materials, vol. 9, no. 17, p. 1804004, 2019.
- S. Zhang, T. Liang, D. Wang et al., “A stretchable and safe polymer electrolyte with a protecting-layer strategy for solid-state lithium metal batteries,” Advancement of Science, vol. 8, article 2003241, 2021.
- Y. Jiang, X. M. Yan, Z. F. Ma et al., “Development of the PEO based solid polymer electrolytes for all-solid state lithium ion batteries,” Polymers, vol. 10, no. 11, p. 1237, 2018.
- J. Bae, Y. Li, J. Zhang et al., “A 3D nanostructured hydrogel-framework-derived high-performance composite polymer lithium-ion electrolyte,” Angewandte Chemie (International Ed. in English), vol. 57, no. 8, pp. 2096–2100, 2018.
- Z. Huang, W. Pang, P. Liang et al., “A dopamine modified Li6.4La3Zr1.4Ta0.6O12/PEO solid-state electrolyte: enhanced thermal and electrochemical properties,” Journal of Materials Chemistry A, vol. 7, no. 27, pp. 16425–16436, 2019.
- K. Liu, X. Li, J. Cai et al., “Design of high-voltage stable hybrid electrolyte with an ultrahigh Li transference number,” ACS Energy Letters, vol. 6, pp. 1315–1323, 2021.
- J. Hu, P. He, B. Zhang, B. Wang, and L.-Z. Fan, “Porous film host-derived 3D composite polymer electrolyte for high-voltage solid state lithium batteries,” Energy Storage Materials, vol. 26, pp. 283–289, 2020.
- J. Wu, Z. Rao, Z. Cheng, L. Yuan, Z. Li, and Y. Huang, “Ultrathin, flexible polymer electrolyte for cost-effective fabrication of all-solid-state lithium metal batteries,” Advanced Energy Materials, vol. 9, no. 46, article 1902767, 2019.
- Z. Wang, L. Shen, S. Deng, P. Cui, and X. Yao, “10 μm-thick high-strength solid polymer electrolytes with excellent interface compatibility for flexible all-solid-state lithium-metal batteries,” Advanced Materials, vol. 33, no. 25, article e2100353, 2021.
- Z. Zhang, Y. Shao, B. Lotsch et al., “New horizons for inorganic solid state ion conductors,” Energy & Environmental Science, vol. 11, no. 8, pp. 1945–1976, 2018.
- C. Wang, K. Fu, S. P. Kammampata et al., “Garnet-type solid-state electrolytes: materials, interfaces, and batteries,” Chemical Reviews, vol. 120, no. 10, pp. 4257–4300, 2020.
- L. Li, H. Duan, J. Li, L. Zhang, Y. Deng, and G. Chen, “Toward high performance all-solid-state lithium batteries with high-voltage cathode materials: design strategies for solid electrolytes, cathode interfaces, and composite electrodes,” Advanced Energy Materials, vol. 11, no. 28, p. 2003154, 2021.
- Q. Zhou, J. Ma, S. Dong, X. Li, and G. Cui, “Intermolecular chemistry in solid polymer electrolytes for high-energy-density lithium batteries,” Advanced Materials, vol. 31, no. 50, article e1902029, 2019.
- G. Liu, W. Weng, Z. Zhang, L. Wu, J. Yang, and X. Yao, “Densified Li6PS5Cl nanorods with high ionic conductivity and improved critical current density for all-solid-state lithium batteries,” Nano Letters, vol. 20, no. 9, pp. 6660–6665, 2020.
- Y. Lu, C. Z. Zhao, H. Yuan, X. B. Cheng, J. Q. Huang, and Q. Zhang, “Critical current density in solid-state lithium metal batteries: mechanism, influences, and strategies,” Advanced Functional Materials, vol. 31, no. 18, p. 2009925, 2021.
- Z. Y. Wei, Z. H. Zhang, S. J. Chen et al., “UV-cured polymer electrolyte for LiNi0.85Co0.05Al0.1O2//Li solid state battery working at ambient temperature,” Energy Storage Materials, vol. 22, pp. 337–345, 2019.
- D. Cai, X. Qi, J. Xiang et al., “A cleverly designed asymmetrical composite electrolyte via in-situ polymerization for high-performance, dendrite-free solid state lithium metal battery,” Chemical Engineering Journal, vol. 435, p. 135030, 2022.
- H. Wan, W. Weng, F. Han, L. Cai, C. Wang, and X. Yao, “Bio-inspired nanoscaled electronic/ionic conduction networks for room- temperature all-solid-state sodium-sulfur battery,” Nano Today, vol. 33, p. 100860, 2020.
- R. Xu, J. Yue, S. Liu et al., “Cathode-supported all-solid-state lithium–sulfur batteries with high cell-level energy density,” ACS Energy Letters, vol. 4, no. 5, pp. 1073–1079, 2019.
Copyright © 2022 Qingya Guo et al. Exclusive Licensee Beijing Institute of Technology Press. Distributed under a Creative Commons Attribution License (CC BY 4.0).