Long-term cycling stability of a SnS2-based covalent organic nanosheet anode for lithium-ion batteries

Abstract

Various SnS₂-based carbonaceous anodes for lithium ion battery (LIB) systems have been developed to enhance the electrochemical performance of SnS₂ materials and to overcome the disadvantages of transition metal sulfides with less interfacial surface sites and low electrochemical conductivity. In this study, we introduced a new strategy of hybridization of SnS₂ and covalent organic nanosheets (CONs) that have high flexibility, high stability in organic electrolytes, and many interfacial surface sites. The CON provided reaction sites for the growth of SnS₂ nanoparticles due to the strong electrostatic interaction between the sulfur heteroatoms of CONs and Sn⁴⁺, resulting in the formation of ultrathin SnS₂ nanoplates on the CON nanosheets. The resulting SnS₂-based CON showed outstanding cyclic stability over 5600 charge/discharge cycles at a current density of 1.0 A g⁻¹ in the LIB system. In particular, the prominent interfacial surface sites of CONs provided large accessible areas for lithium ions, showing stable successive cycling performances with improved electrical and ionic conductivities.