3DG/Se_4.7S_3.3 composites with different morphologies as new all-solid-state lithium storage electrode materials

Abstract

Selenium-sulfur(SexSy) composites can be used as energy storage materials for lithium batteries benefit from their integration of the high capacity of sulfur and the high conductivity of selenium. Herein, we prepared amorphous three dimensional reduced graphene oxide/selenium sulfide(a-3DG/Se4.7S3.3) composites and crystalline 3DG/Se4.7S3.3(c-3DG/Se4.7S3.3) composites by in situ synthesis and hydrothermal methods, respectively, in order to research the effect of different morphologies of 3DG/Se4.7S3.3 composites on the electrochemical properties of all-solid-state lithium batteries. Our study found that the a-3DG/Se4.7S3.3 cathodes displayed greater capacity and outstanding rate performance, with an initial discharge capacity of 926 mAh g-1 and utilization rate of 103% at 1/2C. And a first discharge capacity of up to 706 mAh g-1 at 7C. Although the first discharge capacity of c-3DG/Se4.7S3.3 was 523 mAh g-1, its cycling stability was significantly improved compared with that of a-3DG/Se4.7S3.3 cathodes, and the Coulombic efficiency remained above 97% after 60 cycles at 1/2C. In this work, we investigate the performance of solid-state batteries by preparing new SexSy composites with different morphologies and rational design of electrodes in terms of structure and morphology, which provides ideas for the preparation of electrodes in the future.