Amorphous Titanium Polysulfide Composites with Electronic/Ionic Conduction Networks for All-Solid-State Lithium Batteries.

All-solid-state lithium/sulfide batteries are considered as next-generation high-energy-density batteries with unrivaled safety. However, sulfide cathodes generally suffer from insulating properties and huge volume expansion in all-solid-state lithium batteries. Based on amorphous TiS 4 (a-TiS 4 ), a certain proportion of Super P is introduced to suppress the volume expansion and increase the electronic conductivity. Meanwhile, a Li 7 P 3 S 11 solid electrolyte is in situ coated on the surface of 20% Super P/a-TiS 4 , and the close interfacial contact between the active material and the solid electrolyte constructs a favorable ionic conduction path. As a result, a Li/75% Li 2 S-24% P 2 S 5 -1% P 2 O 5 /Li 10 GeP 2 S 12 /20% Super P/a-TiS 4 @Li 7 P 3 S 11 battery shows a high reversible capacity of 507.4 mAh g -1 after 100 cycles at 0.1 A g -1 . Even the current density increases to 1.0 A g -1 , and it can also provide a reversible capacity of 349.8 mAh g -1 after 200 cycles. These results demonstrate a promising 20% Super P/a-TiS 4 @Li 7 P 3 S 11 cathode material with electronic/ionic conduction networks for all-solid-state lithium batteries.