Application of graphite–solid electrolyte composite anode in all-solid-state lithium secondary battery with Li2S positive electrode

Graphite–solid electrolyte (SE) composite anode, prepared by spark-plasma-sintering (SPS) process, was applied to all-solid-state lithium secondary batteries with lithium sulfide (Li2S) positive electrode. The electrochemical tests demonstrated that the graphite–SE/Li2S cells showed the discharge capacity of ca. 750 mAh·g− 1-Li2S with the average voltage of ca. 1.98 V. Although the discharge capacity was lower than that of the In/Li2S cells (ca. 920 mAh·g− 1-Li2S), the estimated energy density was higher than that (ca. 1490 and 1220 mWh·g− 1-Li2S for graphite–SE/Li2S and In/Li2S cells, respectively), due mainly to its higher average voltage. The graphite–SE/Li2S cells showed improved rate capability as compared with the cells with the graphite + SE blended powder, which was attributable mainly to the reduced interfacial resistance between the graphite and SE particles caused by the SPS process.