Electronic/Ionic Conductive MoS₆-Based Composites for All-Solid-State Lithium Batteries

The transition metal polysulfide cathodes driven by anion redox show high reversible specific capacity, demonstrating great application potential in all-solid-state lithium batteries (ASSLBs). However, their inferior electron/ion conductivities and large volume expansion are critical challenges. In this work, the MoS 6 –10%rGO@15%Li 7 P 3 S 11 cathode material is synthesized and utilized in ASSLBs. The cooperation of reduced graphene oxide (rGO) can significantly mitigate the volume changes of MoS 6 during the cycling and enhance electronic conductivity of the cathode from 2.56 × 10 –8 S cm –1 for MoS 6 to 0.28 S cm –1 for MoS 6 –10%rGO. Besides, a thin Li 7 P 3 S 11 solid electrolyte layer is in situ coated on the surface of MoS 6 –10%rGO, realizing intimate contact. Meanwhile, the ionic conductivity of the MoS 6 –10%rGO@15%Li 7 P 3 S 11 composite reaches 8.4 × 10 –4 S cm –1, 3 orders of magnitude greater than that of MoS 6 with 2.8 × 10 –7 S cm –1 . The ASSLBs utilizing the MoS 6 –10%rGO@15%Li 7 P 3 S 11 cathode deliver an initial discharge specific capacity of 1111.97 mAh g –1 at 0.1 A g –1 . Notably, it achieves a reversible ultrahigh energy density of 1750.94 Wh kg –1 based on the active material at the second cycle. Furthermore, the batteries possess superior cycling stability, maintaining a discharge specific capacity of 729.53 mAh g –1 after 500 cycles at 0.5 A g –1 . This work provides a high-energy-density active material for ASSLBs.