Electrochemical Performance of All‐Solid‐State Li/S Batteries with Sulfur‐Based Composite Electrodes Prepared by Mechanical Milling at High Temperature

Abstract Sulfur–nanocarbon composites were prepared by mechanical milling at high temperature (155 °C), and the electrochemical performance of all‐solid‐state Li/S batteries was investigated with Li 2 S–P 2 S 5 solid electrolytes . We aimed to increase the sulfur content in the sulfur‐based composite electrodes to enhance the energy density in the Li/S batteries. The composites included 50 wt % sulfur, which is twice as high as that in the all‐solid‐state Li/S batteries that use sulfide‐based solid electrolytes reported to date, and high‐temperature mechanical milling resulted in a small sulfur particle size with a large contact area between the particles. The improved composites are mainly responsible for the excellent cyclability (1050 mAh g −1 for 50 cycles), high gravimetric energy density (1007 Wh kg −1 ), and good rate capability of the assembled batteries. These composites are promising positive‐electrode materials for rechargeable Li/S batteries with high energy density. This approach of mechanical milling at high temperature is widely applicable and can be extended to a variety of materials in versatile energy devices as well as rechargeable lithium batteries.