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shortages put forward serious challenges to modern energy storage methods. [1] Under such circumstances, lithium-ion batteries (LIBs) have become more and more widely used in energy storage due to their advantages of high energy density and cycle life. [2] However, conventional LIBs usually use a large amount of flammable, explosive, and volatile organic liquid electrolytes, leading to serious safety problems in use. [3] Moreover, the state-of-the-art LIBs are insatiable in the rising demand for higher energy density. Advanced LIBs based on Li metal anodes (LMBs) could provide higher energy density and become a hot research topic. [4] But the "dead" Li and poor cycling caused by uncontrolled growth of Li dendrites also limit the development of the LMBs.By using solid-state electrolytes (SSE) instead of traditional organic liquid electrolytes, solid-state LMBs are considered to be the most promising energy storage method. SSEs can suppress Li dendrites' formation, thereby fundamentally solving the safety and cycling issues of LMBs. [5] To achieve safe, high energy and power density and better cycle stability, the SSEs require a high diffusion rate including bulk and interface in a wide temperature range, thin and flexible electrolyte films, chemical and mechanical stabilities. However, the SSEs reported so far remain formidable challenges to meet all the above requirements. In general, SSEs can be divided into two categories: inorganic glassy or ceramic electrolytes and solid polymer electrolytes (SPEs). For instance, the inorganic solid electrolyte systems, including the garnet-type and perovskite-type ceramic materials and sulfide-type glass, have been extensively studied for the high conductivity. However, due to the brittle nature, poor processing performance, high interface resistance with the electrode, and high sensitivity to moisture for sulfides, they are still not suitable for wide commercial applications. [6] Various organic SPEs, such as the most studied polyethylene oxide (PEO), [7] the polyacrylonitrile (PAN), [8] the poly(vinylidene fluoride) (PVDF), [9] the polymethyl methacrylate (PMMA), [10] and the polypropylene oxide (PPO), [11] have improved thermal stability and flexibility. Still, their low ionic conductivities restrict the high-power operation of the battery at room temperature. One of the approaches to address above mentioned challenges is to use quasi-solid route by adding the liquid electrolytes (organic solvents or ionic liquid)The urgent need for high energy batteries is pushing the battery studies toward the Li metal and solid-state direction, and the most central question is finding proper solid-state electrolyte (SSE). So far, the recently studied electrolytes have obvious advantages and fatal weaknesses, resulting in indecisive plans for industrial production. In this work, a thin and dense lithiated polyphenylene sulfide-based solid state separator (PPS-SSS) prepared by a solvent-free process in pilot stage is proposed. Moreover, the PPS surface is functionalized to immobilize the...

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The decomposition of commonly used commercial electrolytes under high voltage and the continuous side reactions at the graphite anode make the rapid capacity decay of LiNi0.5Mn1.5O4(LNMO)/graphite full cell during cycling. In this work, we adopt ion-permselective polyphenylene sulfide-based solid state separator (PPS-SSS) for LNMO batteries, PPS-SSS can effectively prevent the proton diffusion, block the HF generated on the LNMO cathode from attacking the anode SEI layer, and mitigate the Mn2+ transfer. The PPS-SSS with anodic polyethylene (PE) protection (PE-PPS-CSSS) significantly improved the cycling performance of LNMO batteries. In the LNMO/Li half-cell system, 93% capacity retention rate can be achieved after 140 cycles at 0.5 C, and in the LNMO/graphite full-cell system, 85% of the initial capacity can be maintained after 100 cycles. Moreover, flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) are applied to explore the interfacial reactions of LNMO/graphite batteries and reveal the key mechanism for the stable cycling using PPS-SSS.

The urgent need for safe and high energy batteries is pushing the battery studies towards the solid-state direction, and the most central question is finding proper solid-state electrolyte. So far, the recently studied electrolyte systems have obvious advantages and fatal weaknesses, resulting in indecisive plans for industrial production. In this work, we propose a thin and dense lithiated polyphenylene sulfide (PPS)-based solid polymer electrolyte prepared by a solvent-free process in a pilot stage. Moreover, the PPS surface is functionalized to immobilize the anions, increase the Li ion transference number to 0.8-0.9, and widen the electrochemical potential window (>5.1 V). At room temperature, the PPS-based quasi-solid electrolyte (PPS-QSSE) exhibits high intrinsic Li+ diffusion coefficient and ionic conductivity (>10-4 S cm-1), excellent thermal stability, and Li+ transport rectifying effect, resulting in homogenous Li-plating on Cu at high current density. Based on the limited Li-plated Cu anode or anode-free Cu, high loadings cathode and high voltage, the Li metal batteries with PPS-QSSEs deliver high energy density (>1000 Wh L-1) and good cycling at high power (900 W L-1) exceeding that of state-of-the-art Li-ion batteries. The results enlighten the mechanism of solid-liquid two phase conduction and promote the solid-state battery towards practicality.