LiCoO2/Li7La3Zr2O12 nanocomposite cathodes synthesized via self-assembled block copolymer templates and used in all-solid-state lithium batteries

Abstract

Nanocomposite cathodes comprising an active cathode material (LiCoO2) and a solid lithium electrolyte (Li7La3Zr2O12) were synthesized by using a self-assembled polystyrene‑b‑poly(4‑vinylpyridine) block copolymer template containing precursors of the active cathode material and solid electrolyte. Calcination at 1023 K was used to remove the block copolymer template and crystallize the active cathode material and solid electrolyte. The molecular weight of the block copolymer template was controlled to optimize the structure of the nanocomposite cathode and maximize capacity. When the nanocomposite cathode that was obtained by using the block copolymer template with the highest molecular weight was used in an all-solid-state lithium battery, the obtained discharge capacity per electrode (98.2 mAh/g) was substantially higher than literature values for other cathodes used in all-solid-state lithium batteries. We conclude that increasing the molecular weight of the block copolymer template allowed for greater dispersion of the precursors and binding of the well-dispersed nanoparticles of active cathode material and solid lithium electrolyte, which promoted the formation of fine conducting paths and an electrochemically effective interface between the active cathode material and solid lithium electrolyte.