Solid-state Li Batteries Research Articles

Interface Engineering and Understanding for the Next-Generation Batteries

Lithium-ion batteries (LIBs) have become the most widely used energy storage systems for portable electronic devices and electric vehicles. With the increasing requirements of high energy density, next-generation batteries, including Li-metal batteries, Na-metal batteries and solid-state batteries, have received huge attention in recent years. For most batteries, the interfacial issues between the electrolyte (both liquid and solid) and electrodes are critical factors affecting the performance of the batteries. Atomic and molecular layer deposition (ALD and MLD) are considered as ideal strategies for overcoming the interfacial issues for the batteries.In this talk, I will introduce our research about interface engineering and understanding for next-generation batteries. i) The interface is one of the key factors for the Li and Na deposition behaviors and battery performances. We developed ALD and MLD approaches to fabricate the artificial interface with significantly improved electrochemical performances and reduced dendrite formation for Li/Na metal anodes. ii) We further design different ALD/MLD thin films to stabilize the interfaces for solid-state Li batteries. iii) We have also developed ex-situ and in-situ synchrotron X-ray techniques for next-generation batteries.

Super Long‐Cycling All‐Solid‐State Battery with Thin Li6PS5Cl‐Based Electrolyte (Adv. Energy Mater. 25/2022)

Solid-State Li Batteries In article number 2200660, Yang Shen, Liangliang Li, Ce-Wen Nan and co-workers report a thin composite solid electrolyte membrane composed of argyrodite sulfide Li6PS5Cl and a polar poly(vinylidene fluoride-co-trifluoroethylene) framework, prepared via a facile electrospinning-infiltration-hot-pressing method. The flexible composite solid electrolyte membrane enables super long-cycling performance of all-solid-state lithium batteries.

Synthesis, structural and conductive properties of Nd doped garnet-type Li7La3Zr2O12 Li-ion conductor

Garnet type solid electrolyte Li7La3Zr2O12 (LLZO) is the most promising candidate among solid electrolytes for all solid state Li batteries. In this work, small amount of Nd doping (5%–20%) to the garnet structure is proposed to improve its ionic conductivity. Nd doped garnet type solid electrolytes for Li-ion batteries were synthesized through a conventional solid state reaction method. The effect of Nd doping on the microstructure, morphology and ionic conductivity of the LLZO was studied by powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and Electrochemical impedance spectroscopy (EIS) methods. Instead of La whose valence is similar to that of Nd, XRD and Raman analyzes revealed that Nd takes the place of the higher valence element Zr. In order to compensate the valence difference, the ratio of Li increases in the structure. On the other side, results showed that Nd doped LLZO samples formed as a mixture of both tetragonal and cubic phases. According to EIS measurements, among the prepared samples, 5% Nd doped LLZO exhibits the highest ionic conductivity of 2.47 × 10−6 S cm−1 at room temperature.

Tailoring the surface energy and area surface resistance of solid-electrolyte polymer membrane for dendrite free, high-performance, and safe solid-state Li-batteries

Solid electrolyte polymer composite enabled solid-state lithium batteries have shown extensive viability for mass production and commerciality for advanced energy storage technology. Most studies of polymer composite electrolyte are produced by solution casting and free-standing methods, where ionic conductors are randomly distributed into the polymeric network, suffering from poor ionic conductivity and agglomeration during charge/discharge cycling. In this work, using the threshold percolation model and critical volume fraction requirement, we have designed a highly efficient garnet-type ion-conducting nanofibrous sheet where ionic conductors of different aspect ratios are dispersed to tune the surface roughness, area surface resistance, and wettability of the developed electrolyte membrane. Moreover, the impact of filler volume fraction and percolation threshold on the surface properties of the membrane, regulating the area interfacial resistance of the Li metal cell has also been examined, which has not been studied so far in the literature. The corresponding high potential cathode-based lithium assembled coin cells exhibit an excellent specific capacity of 170 mAh g −1 at 0.3C, with high capacity retention under ambient circumstances. By optimizing the critical aspect ratio of the fillers and the percolation threshold, a high-performing solid electrolyte membrane can be realized for advanced and safer Li-batteries technology.

A Series of Ternary Metal Chloride Superionic Conductors for High‐Performance All‐Solid‐State Lithium Batteries (Adv. Energy Mater. 21/2022)

Solid State Li Batteries In article number 2103921, Marnix Wagemaker, Xueliang Sun and co-workers report a favorable orthorhombic phase in various Li-M-Cl (M = Dy, Ho, Y, Er, Tm) systems which triggers a significant increase in Li+ diffusivity and reduces the activation energy barrier for diffusion. The findings are expected to aid discoveries around the fundamental chemical theories of the rare earth metal halides and aid exploration of new materials with high Li+ conductivity.

Copper-iron ternary metal fluorides from multi-metallic template fluorination and their first use as cathode in solid state Li-batteries

Conversion cathodes such as metal fluorides are particularly interesting for their theoretical capacities up to 711 mAh/g when used in Li-ion batteries. However, they generally suffer from high hysteresis and/or poor cyclability. To overcome these problems, ternary metal fluorides are being explored to improve electrochemical properties compared to the usual binary fluorides: a polymer electrolyte membrane is also used to avoid undesirable cathode-electrolyte reactions and to assess the compatibility of such cathode materials with All Solid State Batteries (ASSB). Among the multi-metallic models, copper hexacyanoferrate Cu3[Fe(CN)6]2.nH2O from the Prussian blue analogue family (PBA), is fluorinated under pure fluorine gas at selected temperatures according to preliminary thermogravimetric mass spectrometry analyses. Using X-ray absorption spectroscopy and diffraction, an inverse perovskite structure [Cu(H2O)4]3·(FeF6)2 is identified at a fluorination temperature of 140 ​°C and an intimate mixture of CuF2 and FeF3 is formed at 350 ​°C. The cyclic voltammogram of the latter compared to that of a ball-milled sample of similar composition CuF2/FeF3 highlights the advantages of MMTF multi-metallic template fluorination for electrochemical properties, interpreted by the high level of homogeneous dispersion of the redox centers obtained with this method compared to the mechanical milling reference evaluated by SEM. The fluorides are also found to be compatible with the commercial solid polymer electrolyte membrane PEO-LiTFSI (Poly Ethylene Oxide impregnated with Lithium bis(trifluoromethanesulfonyl)imide), underlining the suitability of the MMTF-prepared cathodes for use in the ASSB.

Fluoride-Rich Solid Electrolyte Membrane in Solid-State Li–S Batteries: Improvement of Lithium Cycle Stability and Shuttle Effects

Although employing solid polymer electrolytes (SPEs) in solid-state Li–S batteries (SSLSBs) is a promising approach to obtain both high energy density and safety, the actual cycle property is still rather unsatisfactory. In this work, by combining experiments and calculations, we revealed that a coupling effect between lithium polysulfides (LiPSs) and polyethylene oxide (PEO)-based SPEs was the cause of interfacial instability of the poor cyclelife of lithium anode in SSLSBs. In light of this, a fluorine-rich polymer perfluoropolyether alcohol (PFA) was introduced as an interfacial layer between the SPE and lithium anode. PFA decouples from LiPSs because of the shielding effect of F in PFA on the electron cloud of O and the spatial effect. As a result, the PFA interlayer plays a role in preventing corrosion of the lithium metal from LiPSs and the electrochemical decomposition of PEO-based SPEs. The PEO-based SSLSBs with PFA showed a discharge capacity of 627.4 mA h gS–1 after 100 cycles at 0.05 mA cm–2 and 60 °C. This work emphasized the significance of SPE decoupling from LiPSs in SSLSBs and provided a feasible guidance for the design of high-performance SSLSBs.

Phase Stability of Garnet Solid-Electrolyte Interfacing with Various Cathodes in All-Solid-State Batteries

Garnet-structured Li6.75La3Zr1.75Ta0.25O12 (LLZTO) is one of the most promising electrolyte materials for solid-state Li batteries (SS-LiB). The design and fabrication of a good cathode/electrolyte interface is an important criterion for the SS-LiB. In this work, we performed a systematic study on the impact of cathode crystal structure and chemical compositions on their chemical stabilities against the LLZTO at elevated temperatures, which are required for their adhesion during cell fabrication processes. X-ray Diffraction (XRD) and Rietveld refinement analyses revealed the chemical stabilities of various cathode materials in contact with the LLZTO. While layered LiCoO2 cathode showed good stability in contact with LLZTO to 900 °C, LiNiO2 or Ni-rich LiNixMnyCo1−x−yO2 (NMC) cathodes suffered from the formation of La4NiLiO8 due to La-diffusion from LLZTO. Mn-rich LiMn2O4 spinel and layered LiNi1/3Mn1/3Co1/3O2 cathodes suffered from the formation of La2Zr2O7 due to Li-diffusion and production of Li2MnO3. As a result, LiNi0.6Mn0.2Co0.2O2, having an ideal balance of Ni/Mn/Co composition, or Li2MnO3 containing cathodes such as Li1.2Ni0.15Mn0.55Co0.1O2 were found to have excellent phase stability as the cathodes for LLZTO-based SS-LiBs.

A Parametric Study on the Preparation of Sulfur-Graphene Composites for Rechargeable Aqueous and Solid-State Li-S Batteries

A Parametric Study on the Preparation of Sulfur-Graphene Composites for Rechargeable Aqueous and Solid-State Li-S Batteries

A self-regulated gradient interphase for dendrite-free solid-state Li batteries

A functional gradient lithium anode (FGLA), where a LiF-rich layer faces garnet side and gradually changes to a LiAl-rich layer facing Li side, effectively prevents solid-state electrolytes from dendrite penetration at high current densities.

Perspective of polymer-based solid-state Li-S batteries

Energy Materials is an interdisciplinary international open access, online journal dedicated to communicating recent progresses related to materials science and engineering in the field of energy conversion and storage. The journal publishes Articles, Communications, Mini/Reviews and Perspectives with original research works focusing on the challenges of sustainable energy for the future.

Ionic Rectification across Ionic and Mixed Conductor Interfaces.

In electrochemical devices, it is important to control the ionic transport between the electrodes and solid electrolytes. However, it is difficult to tune the transport without applying an electric field. This paper presents a method to modulate the transport via tuning of the electrochemical potential difference by controlling the electronic states at the interfaces. We fabricated thin-film solid-state Li batteries using LiTi2O4 thin films as positive electrodes. The spontaneous Li-ion transport between the solid electrolyte and LiTi2O4 is controlled by tuning the electrochemical potential difference via use of an electrically conducting Nb-doped SrTiO3 substrate. This study establishes the foundation for rectifying the ionic transport via electronic energy band alignment.

Cross-Linked Polypropylene Oxide Solid Electrolyte Film with Enhanced Mechanical, Thermal, and Electrochemical Properties via Additive Modification

Benefiting from the flexibility and low cost, polymer electrolytes are widely used in ultra-thin solid lithium-ion batteries. However, low room-temperature ion conductivity and poor mechanical and thermal stability are key defects hindering the wide application of the polymer solid-state electrolyte. In this work, a cross-linked polypropylene oxide (PPO) polymer solid electrolyte film with excellent mechanical, thermal and electrochemical properties was prepared by introducing the cellulose skeleton, polyglycol (peg400), and zirconia (ZrO2) additives. The cellulose skeleton and peg400 enhance the flexibility, tensile strength and thermal stability(>200 °C) of the electrolyte film, while ZrO2 promotes the movement of polymer segments and the dissociation of lithium salts to improve the ionic conductivity (6.67 × 10–4 S cm–1 at room temperature) and increase the potential window (>4.6 V vs Li/Li+) of the electrolyte. This composite electrolyte film can be used in LiFePO4(LFP) and LiNi0.6Co0.2Mn0.2 (NCM622) solid-state batteries and shows good cycling stability with 600 cycles for LFP. This rigid-flexible composite solid electrolyte film with high ion conductivity and good mechanical and thermal properties has good prospects for application in solid-state Li batteries.

Garnet-Based Composite Cathodes for Polymer-Ceramic Solid-State Li Batteries

Ceramic solid-state Li batteries (SSLBs) with high capacity composite cathodes have a huge potential to outperform conventional Li-ion batteries [1]. Among the most promising ceramic electrolytes is garnet-based Li7La3Zr2O12 (LLZ), which has a wide electrochemical window, stability vs metallic Li, and good Li-ion conductivity at room temperature [1]. However, so far, the electrochemical cycling stability of all ceramic solid-state SSLBs is low [1]. The volume changes in the cathode active materials (CAMs) during cycling can cause cracks at the rigid CAM/ceramic electrolyte interface if the density of the mixed cathode is low. To mitigate the detrimental effects of crack formation, polymer electrolyte can be added to fill the cracks could and ensure a good contact between CAM and ceramic electrolyte. Such a concept is called polymer-ceramic SSLB [2].LLZ-based polymer ceramic SSLBs have already shown good electrochemical properties. Commonly the cells are constructed based on a LLZ separator with a dense and porous side that are manufactured by tape-casting [2, 3]. The tape-casting process is not straight forward as it requires the preparation of a slurry with organic solvents. Furthermore, the grain morphology has a major impact on the final LLZ microstructure. Afterwards, the tape-casted LLZ separator is conventionally sintered and grain growth and loss of volatile elements, such as Li, occurs. The sintered LLZ separator is then infiltrated by CAM solution [3]. After drying the CAM solution the polymer electrolyte is added.In a powder-based process, co-sintering the LLZ and CAM simplifies the manufacturing. Another advantage is that the porous LLZ framework is stabilized by the CAM and allows to reduce the LLZ amount in the porous framework in order to achieve higher CAM loadings. However, the high sintering temperature and long dwell time for the sintering of garnet-based LLZ electrolyte lead to reactions with cathode active materials (CAMs) and hamper the manufacturing of composite cathodesA reduction in sintering temperature and dwell time can be achieved by advanced sintering techniques, such as Field-Assisted-Sintering-Technique/Spark Plasma Sintering (FAST/SPS). FAST/SPS applies rapid Joule heating and mechanical pressure. This shortens the required processing times due to faster heating and an increased sintering rate and reduces the sintering temperatures. By that less grain growth is observed, and the loss of volatile elements is reduced.Recently, we showed, that FAST/SPS can co-sinter LLZ and LiCoO2 (LCO) and allows the preparation of an LLZ/LCO composite cathode in one step. The LLZ/LCO phases are clean and provide a low interface impedance [4]. Another advantage is that the thickness of the composite cathode is easily scalable. However, the obtained density was around 95 % and only closed porosity was observed, that prevents the polymer infiltration.In this work, the FAST/SPS process is adjusted to manufacture phase pure porous LLZ/LCO-composite cathodes in one sintering step. The porosity is easily controllable, without the requirement of pore former by the applied pressure during FAST/SPS. Infiltration of polymer electrolyte into the pores within the composite cathode leads to significantly lowered interfacial impedances. The porous composite cathode can be assembled into a polymer ceramic SSLB by attaching it to an anodic half-cell (separator and anode) to demonstrate the functionality of the presented concept.

Optimization of Cycling Performance for CNT Impregnated Sulfur Composite Cathode Using LiBH4 as Solid Electrolyte for All Solid State Li-S Batteries

In this contribution we are reporting the optimization of cycling performance of CNT-S composite cathode with conductive solid electrolyte lithium borohydride (LiBH4) for solid state lithium sulfur batteries. The composite cathode was fabricated via different composition of S and CNTs with acetylene dark (AB) and LiBH4 by ball-milling. Electrochemical performance has been tested by galvanostatic charge-discharge at 0.1C c-rate showing initial charge capacity 1459 mAh/g and constant capacity upto 398.045mAh/g over no of cycles. Our results indicate a significant improvement in rate and cycling performance of LiBH4 solid electrolyte.

Halide Solid-State Electrolytes: Synthesize and the Atmospheric Stability Study

Rechargeable all-solid-state Li batteries (ASSLBs) are considered as the next generation of electrochemical energy storage systems. Development of solid-state electrolytes (SSEs), which are key materials for ASSLBs, is therefore one of the most important subjects in modern energy storage chemistry. Thus, various types of electrolytes such as polymer-, oxide-, and sulfide-based SSEs have been developed to date and the development of new superionic conductors is still ongoing. Halide SSEs (Li-M-X, M is a metal element, and X is a halogen) are emerging as promising candidates with a number of attractive properties (oxidative stability and interfacial compatibility, etc.). [1] For example, halide SSEs show advantages including high ionic conductivity, wide electrochemical stability windows (0.36-6.71 V vs. Li/Li+), and improved chemical stability toward cathode materials compared to other SSEs. [2-4] Moreover, some of the halide SSEs (such as Li3InCl6 developed by our group) can be directly synthesized in a water solvent with the capability of large-scale production, thus removing the need for special apparatus or handling in an inert atmosphere.In this talk, (i) I will demonstrate the new and salable water-mediated synthesis method of the highly conductive Li3InCl6 halide SSE [5]. (ii) I will report the anion sublattice evolution effect on Li+ conductivity for halide SSEs [6]. I will also show the humidity stability and degradation chemistry of metal halide SSEs investigated by advanced in-situ and operando synchrotron techniques [6-7]. In the end, direct synthesis of halide SSEs on cathode materials by the water-mediated route that has been used to eliminate the interfacial challenges of ASSLBs or act as an interfacial modifier for high-performance all-solid-state Li-O2 batteries will be discussed [8-9].References X. Li, J. Liang, X. Yang, K. R. Adair, C. Wang, F. Zhao, X. Sun, Progress and Perspectives of Halide-based Lithium Conductors for All-Solid-State Lithium Batteries. Energy Environ. Sci., 2020, 13, 1429-1461. J. Liang, X. Li, S. Wang, K. R. Adair, W. Li, Y. Zhao, C. Wang, Y. Hu, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, Y. Mo, X. Sun. Site-Occupation-Tuned Superionic LixScCl3+x Halide Solid Electrolytes for All-Solid-State Batteries. J. Am. Chem. Soc., 2020, 142, 7012-7022. X. Li, J. Liang, J. Luo, M. Banis, C. Wang, W. Li, S. Deng, C. Yu, F. Zhao, Y. Hu, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, K. R. Adair, X. Sun, Air-stable Li3InCl6 electrolyte with high voltage compatibility for all-solid-state batteries, Energy Environ. Sci., 2019, 12, 2665-2671. C. Yu, Y. Li, K. R. Adair, W. Li, K. Goubitz, Y. Zhao, M. J. Willans, M. A. Thijs, C. Wang, F. Zhao, Q. Sun, S. Deng, J. Liang, X. Li, R. Li, T. Sham, H. Huang, S. Lu, S. Zhao, L. Zhang, L. Eijck, Y. Huang, X. Sun, Tuning ionic conductivity and electrode compatibility of Li3YBr6 for high-performance all solid-state Li batteries, Nano Energy, 2020, 77, 105097. X. Li, J. Liang, N. Chen, J. Luo, K. R. Adair, C. Wang, M. Banis, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, X. Sun, Water-Mediated Synthesis of Superionic Halide Solid Electrolyte, Angew. Chem. Int. Ed., 2019, 58, 16427-16432. X. Li, J. Liang, K. R. Adair, J. Li, W. Li, F. Zhao, Y. Hu, T. Sham, L. Zhang, S. Zhao, S. Lu, H. Huang, R. Li, N. Chen, X. Sun, “Origin of Superionic Li3Y1-xInxCl6 Halide Solid-Electrolytes with High Humidity Tolerance” Nano Lett., 2020, 20, 4384-4392. W. Li, J. Liang, M. Li, K. Adair, X. Li, Y. Hu, Q. Xiao, R. Feng, R. Li, L. Zhang, S. Lu, H. Huang, S. Zhao, T. Sham, X. Sun, Unraveling the Origin of Air Stability of Halide Solid-State Electrolytes by In situ and Operando Synchrotron X-ray analytical techniques, Chem. Mater., 2020, 32, 7019–7027. C. Wang, J. Liang, M. Jiang, X. Li, S. Mukherjee, K. Adair, M. Zheng, Y. Zhao, F. Zhao, S. Zhang, R. Li, H. Huang, S. Zhao, L. Zhang, S. Lu, C. Singh, X. Sun, Interface-Assisted In-situ Growth of Halide Electrolytes Eliminating Interfacial Challenges of All-Inorganic Solid-State Batteries. Nano Energy, 2020, 76, 105015. C. Zhao, J. Liang, X. Li, N. Holmes, C. Wang, J. Wang, F. Zhao, S. Li, Q. Sun, X. Yang, J. Liang, X. Lin, W. Li, R. Li, S. Zhao, H. Huang, L. Zhang, S. Lu, X. Sun, Halide-based solid-state electrolyte as an interfacial modifier for high performance solid-state Li–O2 batteries. Nano Energy, 2020, 75, 105036.

Practical considerations in designing solid state Li-S cells for electric aviation

The development of high-energy, high-safety, and high-power batteries beyond electric automotive standards is critical for future electric aviation applications. Non-volatile solid-state electrolytes (SSE) offer many promising advantages over traditional flammable liquid electrolytes. SSE may become an enabling technology for certain battery chemistries by preventing detrimental interactions that occur with liquid electrolytes, for example preventing dissolution of lithium-sulfur intermediates common in traditional liquid organic solvents. However, significant manufacturing challenges must be overcome before the adoption of such technology. One of the main challenges is the fabrication of sufficiently thin electrolyte layer to maximize specific energy of the solid-state cell. In this work we first show the feasibility in the assembly of an all solid-state battery via the development of composite SSE with ionic conductivity above 0.2mS/cm and thicknesses on the order of 40 micron through a tape-casting technique. With Li/Al alloy as the anode and TiS2 as the active cathode material, the resultant solid-state battery with a thin electrolyte layer and excellent cathode-electrolyte interface represents a prototype vision on a potential solid-state cell required for electric aviation. A detailed parameter analysis is further presented on the influence of the various cell metrics, such as electrolyte thickness, carbon content, active material utilization, and excess lithium, on the cell specific energy. The implications in the optimization of these required parameters to enable practical solid-state Li-S batteries for electric aviation are discussed.

Interconnected cathode-electrolyte double-layer enabling continuous Li-ion conduction throughout solid-state Li-S battery

All-solid-state lithium (Li) batteries with high energy density are a promising solution for the next-generation energy storage systems in large-scale devices. To simultaneously overcome the challenges of poor ionic conduction of solid electrolytes and shuttling of active materials, we introduce a functional electrolyte-cathode bilayer framework with interconnected LLAZO channels from the electrolyte into the cathode for advanced solid-state Li-S batteries. Differing from the traditional solid-state batteries with separated layer compositions, the introduced bilayer framework provides ultrafast and continuous ion/electron conduction. Instead of transferring Li+ across the polymer and garnet phases which involve huge interfacial resistance, Li+ is directly conducted through the LLAZO channels created continuously from the cathode layer to the solid electrolyte layer, significantly shortening the diffusion distance and facilitating the redox reaction of sulfur and sulfides. A stable cycle life is demonstrated in the prototype Li-S solid-state batteries assembled with the introduced LLAZO-LLAZO@CNF interconnected bilayer framework. High capacity is obtained at room temperature, indicating the superior electrochemical properties of the bilayer framework that result from the unique design of the interconnected LLAZO garnet phase.

Optimization of Cycling Performance for CNT Impregnated Sulfur Composite Cathode Using LiBH4 as Solid Electrolyte for All Solid State Li-S Batteries

In this contribution we are reporting the optimization of cycling performance of CNT-S composite cathode with conductive solid electrolyte lithium borohydride (LiBH4) for solid state lithium sulfur batteries. The composite cathode was fabricated via different composition of S and CNTs with acetylene dark (AB) and LiBH4 by ball-milling. Electrochemical performance has been tested by galvanostatic charge-discharge at 0.1C c-rate showing initial charge capacity 1459 mAh/g and constant capacity upto 398.045mAh/g over no of cycles. Our results indicate a significant improvement in rate and cycling performance of LiBH4 solid electrolyte.

Scale-up processing of a safe quasi-solid-state lithium battery by cathode-supported solid electrolyte coating

A solid-state lithium metal battery has been considered as a promising next-generation energy storage system for its high safety. Great challenges remain for the scale-up fabrication of solid-state Li batteries with the current manufacturing facility used for liquid Li-ion batteries. In this work, a scale-up route is employed to fabricate quasi-solid-state Li batteries by cathode-supported coating of a solid electrolyte combined with in-situ polymerization for interfacial modification. A Li1.3Al0.3Ti1.7(PO4)3 (LATP) layer with a polyvinylidene fluoride (PVDF) binder is coated on the LiCoO2 cathode as the solid electrolyte. A iquid electrolyte containing a poly(ethylene glycol) methyl ether acrylate (PEGMEA) monomer is injected during the battery fabrication process followed by in-situ polymerization. The in-situ formed gel electrolyte acts as a soft interface to enhance the contact between the electrode and the solid electrolyte. A coin-type quasi-solid-state Li||LiCoO2 battery delivers a high capacity of 122 mAh g−1 and retains 81% of its initial capacity after 100 cycles at 0.5 C and 60 °C. A pouch-type Li||LiCoO2 battery is also fabricated using a commercial LiCoO2 electrode and shows a satisfactory safety performance and stable cycling at 0.5 C.