In situ synthesized dilithium rhodizonate/carbon nanotube composite cathodes for high-performance all-solid-state lithium batteries

Abstract

The construction of all-solid-state organic batteries is considered as one of the ideal means to solve the dissolution of organic electrode materials (OEMs). Unfortunately, the interface contact problem caused by the volume expansion of OEMs has been a key constraint in the development of all-solid-state organic batteries. Here we report an in situ method for fabricating nano-sized dilithium rhodizonate/carbon nanotubes (Li2C6O6/CNTs) composites as cathodes for high-performance all-solid-state batteries (ASSBs) based on Li6PS5Cl sulfide electrolyte. The in situ formed Li2C6O6/CNTs composite with uniform cross-linking distribution of each component promotes facile electron conduction in cathodes and adapts to volume expansion of Li2C6O6, which significantly outperforms the conventional grinding Li2C6O6/CNTs composite. Besides, the sulfide electrolyte Li6PS5Cl can avoid the dissolution of Li2C6O6 during discharge/charge processes. As a result, the Li2C6O6 cathode demonstrates an impressive capacity retention of 63.5 % after 200 cycles at room temperature, markedly surpassing the performance of Li2C6O6 in liquid electrolyte (21 % after 50 cycles). Moreover, the capacity of Li2C6O6 can retain 141.2 mAh⋅g−1 at 5 C, which is more superior than most of ASSBs with OEMs reported so far. This work proposes an effective design strategy to achieve high-performance organic composite cathodes for ASSBs.