Rationally designed C/Co₉S₈@SnS₂ nanocomposite as a highly efficient anode for lithium-ion batteries

Abstract

Nanostructured transition metal sulfides are promising anode materials for lithium-ion batteries. Nevertheless, it is still a great challenge to prepare capacity-improved electrodes without reducing their rate capability and cycle stability. In this paper, we present a C/Co9S8@SnS2 composite material by loading SnS2 nanocrystals onto MOF-derived C/Co9S8 nanostructures. The C/Co9S8@SnS2 composite has multiple active sites to store lithium ions. The specific capacity reaches 3.1 mAh cm−2 when the current density is 0.224 mA cm−2. The asynchronous electrochemical reaction between Co9S8 and SnS2 offsets the volume expansion of the anode material. Meanwhile, the compact adhesion of carbon layers on the interfaces suppresses the destruction of the anode during the charging–discharging processes. Consequently, the synthesized electrode presents favorable capacity with high current density or under long-term cycling conditions. The prepared battery has a reversible specific capacity of 0.452 mAh cm−2 and a coulomb efficiency of 99.7% after 500 cycles with a high current density of 2.24 mA cm−2. The research results obtained in this work provides a feasible strategy to improve the performance of electrodes systematically.

Lithium Storage Properties of TiC‐Modified SnS2 Nanosheets

“…To address these flaws, many researchers try to improve electrochemical performances of SnS 2 ‐based anodes for Li‐ion batteries by choosing different materials and methods [9–23] . One strategy is to synthesize nanostructured SnS 2 , in forms including nanosheets, [11] nanospheres, [9] and nanowires [12] .…”

“…The nanostructure can ameliorate the huge volume change in SnS 2 during cycling and also increase electrode/electrolyte contact areas, thus shortening the diffusion path of Li + : however, nanostructured SnS 2 is prone to severe structural agglomeration during cycling, degrading of its electrochemical performance [13] . Furthermore, another effective strategy is modifying the SnS 2 nanostructure with conductive materials, such as carbon nanotubes, [14] carbon nanofibers, [15] or graphene, [10,16] enhancing both its electronic conductivity and structural stability [17] . Among them, graphene is widely used as a coating material on account of its excellent electronic conductivity, high specific surface area, and superior mechanical flexibility; [18] however, excessive numbers of surface defects on graphene sheets will cause irreversible intercalation of lithium, resulting in higher losses after the first cycle.…”

“…To address these flaws, many researchers try to improve electrochemical performances of SnS 2 -based anodes for Li-ion batteries by choosing different materials and methods. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] One strategy is to synthesize nanostructured SnS 2 , in forms including nanosheets, [11] nanospheres, [9] and nanowires. [12] The nanostructure can ameliorate the huge volume change in SnS 2 during cycling and also increase electrode/electrolyte contact areas, thus shortening the diffusion path of Li + : however, nanostructured SnS 2 is prone to severe structural agglomeration during cycling, degrading of its electrochemical performance.…”

“…[13] Furthermore, another effective strategy is modifying the SnS 2 nanostructure with conductive materials, such as carbon nanotubes, [14] carbon nanofibers, [15] or graphene, [10,16] enhancing both its electronic conductivity and structural stability. [17] Among them, graphene is widely used as a coating material on account of its excellent electronic conductivity, high specific surface area, and superior mechanical flexibility; [18] however, excessive numbers of surface defects on graphene sheets will cause irreversible intercalation of lithium, resulting in higher losses after the first cycle. Besides, most of the preparation processes are too complex, expensive, and time-consuming.…”

Synthesis of porous hollow spheres Co@TiO 2-x -carbon composites for highly efficient lithium-ion batteries

“…However, it has a relatively low theoretical gravimetric capacity, which cannot achieve the demand of LIBs industry for high theoretical capacity and energy density. Therefore, a variety of alternative anode materials have been widely studied [3][4][5]. Among all proposed candidates for the anode, TiO 2 has the advantages of high theoretical capacity, excellent Li-ion storage performances and environmental friendliness.…”