NASICON‐type structured Li1.5Al0.5Ge1.5(PO4)3–xLi2O Li‐ion‐conducting glass–ceramics were successfully prepared from as‐prepared glasses. The differential scanning calorimetry, X‐ray diffraction, nuclear magnetic resonance, and field emission scanning electron microscope results reveal that the excess Li2O is not only incorporated into the crystal lattice of the NASICON‐type structure but also exists as a secondary phase and acts as a nucleating agent to considerably promote the crystallization of the as‐prepared glasses during heat treatment, leading to an improvement in the connection between the glass–ceramic grains and hence a dense microstructure with a uniform grain size. These beneficial effects enhance both the bulk and total ionic conductivities at room temperature, which reach 1.18 × 10−3 and 7.25 × 10−4 S/cm, respectively. In addition, the Li1.5Al0.5Ge1.5(PO4)3–0.05Li2O glass–ceramics display favorable electrochemical stability against lithium metal with an electrochemical window of about 6 V. The high ionic conductivity, good electrochemical stability, and wide electrochemical window of LAGP–0.05LO glass–ceramics suggest that they are promising solid‐state electrolytes for all solid‐state lithium batteries with high power density.

Li3VO4 is a potential anode for Li‐ion batteries owing to its safe discharge plateau and high capacity, but the reported reversible capacity is still far from its theoretical value (592 mAh g−1). Here, for the first time, a Li3VO4 anode is reported with reversible capacity approaching the theoretical value. Li3VO4 aggregates hybridized with carbon (Li3VO4/C) are first fabricated, and then dramatically transform into well dispersed Li3VO4 nanocrystals (NCs) anchoring on carbon nanoflakes (NFs) by electrochemical reconstruction. In the Li3VO4/C NC‐on‐NF structures, the small‐sized Li3VO4 NCs, the flexible carbon NFs, and the good dispersity provide high Li‐ion storage, electronic conductivity and stability, respectively. Resultingly, outstanding electrochemical performance of the Li3VO4/C is achieved with discharge and charge capacities of 542 and 541 mAh g−1 after 300 cycles at a specific current of 150 mA g−1. After 1000 cycles at a specific current of 2000 mA g−1, the discharge and charge capacities are maintained at 422 and 421 mAh g−1. When matching with a 4 V cathode, the specific energy density of the Li3VO4/C is 4.2 times of Li4Ti5O12 and 1.2 times of graphite, and the volumetric energy density is 3.2 times of Li4Ti5O12 and 1.4 times of graphite.

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All-solid-state lithium batteries employing inorganic solid electrolytes have been regarded as an ultimate solution to safety issues because of their features of no leakage as well as incombustibility and they are expected to achieve higher energy densities owing to their simplified structure. Two-dimensional transition-metal dichalcogenides exhibit a great potential in energy storage devices because of their unique physical and chemical characteristics. In this work, 50 nm thick highly crystalline layered VS (hc-VS) nanosheets are prepared by a solvothermal method, and their electrochemical performances are evaluated in Li/75% LiS-24% PS-1% PO/LiGePS/hc-VS all-solid-state lithium batteries. At 50 mA g, hc-VS nanosheets show a high reversible capacity of 532.2 mAh g after 30 cycles. Moreover, stable discharge capacities are maintained at 436.8 and 270.4 mAh g at 100 and 500 mA g after 100 cycles, respectively. The superior rate capability and cycling stability are ascribed to the better electronic conductivity and well-developed layered structure. In addition, the electrochemical reaction kinetics and capacity contributions were analyzed via cyclic voltammetry measurements at different scan rates.