It is a highly relevant topic concerning how to improve the electrochemical performance of anode materials for the next generation lithium-ion batteries (LIBs). Herein, for the first time, we report a facile and controllable approach to modify MoS ₂ nanosheets, a typical 2D material, as an anode material for advanced LIBs via oxygen plasma engineering. An oxygen plasma treatment not only generates vacancies/defects but also incorporates heteroatom doping to form Mo–O–C bonds. This unique hybrid specialty enables the oxygen-plasma-treated MoS ₂ to achieve superior electrochemical performance with high reversible capacities, a long-term cycle life, and good rate capabilities. The plasma-assisted modification is believed to be applicable for other 2D materials as an efficient anode for energy storages.

Sulfide solid electrolytes possess high ionic conductivity and moderate dendrite suppression capability, but rather poor compatibility against oxide cathodes and metallic Li. Here, we report O-doped Li₆PS₅Br as solid electrolyte synthesized by a facile solid-state sintering. Different from other O-incorporated sulfides, the O atoms in Li₆PS_5-xO_xBr prefer to substitute the S atoms at free S²⁻ sites rather than those at the PS₄ tetrahedra. Remarkably, without deteriorating the ionic conductivity, this inorganic solid electrolyte with O doping exhibits comprehensively enhanced properties including excellent dendrite suppression capability, superior electrochemical and chemical stability against Li metal as well as high voltage oxide cathodes, and good air stability. Li(Ni_0.8Co_0.1Mn_0.1)O₂ and LiCoO₂-based all-solid-state batteries with Li₆PS_4.7O_0.3Br electrolyte deliver high specific capacity, superior rate capability, and outstanding cycling stability accompanied with low interfacial resistivity. This type of inorganic solid electrolytes is promising for all-solid-state batteries with high energy density.

Li₆PS₅X (X = Cl, Br, I) argyrodites possess high ionic conductivity but with rather scattered values due to various processing conditions. In this work, Li₆PS₅X solid electrolytes were prepared by solid-state sintering or mechanical alloying and optimized with or without excess Li₂S. Solid-state sintering prefers excess Li₂S, whereas mechanical alloying prefers stoichiometric Li₂S to synthesize high-purity samples with high ionic conductivity. Solid-state sintering is also more suitable than mechanical milling for high ionic conductivity. Li₆PS₅Cl with the highest ionic conductivity among Li₆PS₅X was comprehensively characterized for electrochemical performance and air stability. MoS₂/Li₆PS₅Cl all-solid-state batteries assembled with Li₆PS₅Cl-coated MoS₂ as cathode and with Li₆PS₅Cl as solid electrolyte demonstrate high capacity and good cycling stability.

Exploration of advanced anode materials is a highly relevant research topic for next generation lithium-ion batteries. Here, we report severe lattice distorted MoS₂ nanosheets with a flower-like morphology prepared with PEG400 as additive, which acts not only as surfactant but importantly, also as reactant. Notably, in the absence of a carbon-related incorporation/decoration, it demonstrates superior electrochemical performance with a high reversible capacity, a good cycling stability, and an excellent rate capability, originated from the advantages of synthesized MoS₂ including enlarged interlayer spacing, 1T-like metallic behavior, and coupling of Mo–O–C (and Mo–O) hetero-bonds. PEG-assisted synthesis is believed applicable to other anode materials with a layered structure for lithium-ion batteries.

Garnet-type Li₇La₃Zr₂O₁₂ solid electrolytes were commonly prepared by two steps solid-state reaction method, which undergoes high temperature over 1000 °C and thus inevitable for lithium volatilization and formation of secondary phases. Here, we propose a new intergrain architecture engineering of a solution method, to avoid high temperature sintering for preparing lithium halide (LiX) coated garnet-type solid electrolytes, which contain Al and Ta co-doped Li₇La₃Zr₂O₁₂ (Li_6.75La₃Zr_1.75Ta_0.25O₁₂, LLZTO) synthesized at 900 °C with cubic structure. Owing to the increased relative density, the improved formability, and the altered ion transport mode from point to face conduction by LiX coating on LLZTO grains, LiX-coated LLZTO samples demonstrate a good Li dendrite suppression ability and a high ionic conductivity that is three orders of magnitude higher than pristine LLZTO. In another way, this result demonstrates the critical role of the grain boundaries on the ion transport for oxide superionic conductors. The present coating method provides a new strategy to prepare brittle solid electrolytes avoiding high temperature sintering.

A comprehensive research coupling experiment and computation has been performed to understand the phase transition of Na₃SbS₄ and to synthesize cubic Na₃SbS₄ (c-Na₃SbS₄), a high temperature phase of Na₃SbS₄ that is difficult to be preserved when cooled down to ambient temperature. The formation of c-Na₃SbS₄ is verified by Rietveld refinement, nuclear magnetic resonance spectroscopy as well as electrochemical impedance spectroscopy. Unlike tetragonal Na₃SbS₄ (t-Na₃SbS₄) appearing phase transition at high temperature, c-Na₃SbS₄ is stable not just at room temperature but also sustaining thermal cycling up to at least 200 °C. Both experiment and theoretical calculation reveal that the ionic conductivity of c-Na₃SbS₄ is higher than that of t-Na₃SbS₄, though the values are in the same order of magnitude. Both structures allow fast ion transport. All-solid-state cells with c-Na₃SbS₄ solid electrolyte demonstrate superior Coulombic efficiency, high specific capacity, and relatively good cycling stability. Na₃SbS₄ solid electrolyte is promising for all-solid-state sodium-ion batteries.