One‐dimensional NiS‐CNT@Li7P3S11 nanocomposites as ionic/electronic additives for LiCoO2 based all‐solid‐state lithium batteries

Increasing active material content is critical to realize high energy density for all-solid-state lithium batteries (ASSLBs), which is generally impeded by limited ionic/electronic conductions in cathode layer. Herein, one-dimensional NiS-CNT@Li 7 P 3 S 11 nanocomposites are synthesized by wet chemistry method and possess high mixed ionic/electronic conductivities. When employed as additives for LiCoO 2 , the NiS-CNT@Li 7 P 3 S 11 nanocomposites can efficiently improve the electrochemical performances of LiCoO 2 cathode in the ASSLBs. Specifically, the resultant Li/75%Li 2 S-24%P 2 S 5 -1%P 2 O 5 /Li 10 GeP 2 S 12 /LiCoO 2 -5%NiS-CNT@Li 7 P 3 S 11 ASSLBs with 70 wt% LiCoO 2 content deliver a reversible capacity of 114.3 mAh g −1 after 50 cycles under 0.1 C and 99.6 mAh g −1 at 0.5 C after 100 cycles at room temperature . Even if the active material LiCoO 2 content increases to 80%, a high reversible discharge capacity of 124 mAh g −1 can be achieved at 0.05 C after 25 cycles. Obviously, the excellent electrochemical performances are attributed to the improved ionic/electronic conductivities with assistance of NiS-CNT@Li 7 P 3 S 11 . This work provides an efficient strategy to design cathode materials with high ionic/electronic conductivities and paves the way for the practical application of ASSLBs.