All-solid-state Li/S batteries with Li2S–P2S5 glass–ceramic electrolytes were fabricated and their electrochemical performance was examined. Sulfur–carbon composite electrodes were prepared by grinding with a mortar and milling with a planetary ball-mill apparatus. Milling of a mixture of sulfur, acetylene black and the Li2S–P2S5 glass–ceramic electrolyte resulted in the amorphization of sulfur and a reduction in the particle size of the mixture. The charge–discharge properties of all-solid-state cells with the composite electrode were investigated at temperatures from −20°C to 80°C. The cells retained a reversible capacity higher than 850mAhg−1 for 200 cycles under 1.3mAcm−2 (333mAg−1) at 25°C. The cell performance was influenced by the crystallinity of sulfur and the particle size of the electrode material, whereby improved contact among the electrode components achieved by milling contributed to enhancement of the capacity of an all-solid-state Li/S cell.