▎ 摘　　要

Bimetallic NixCo3-xS4 (x = 1 or 2) with synergistic effect is a promising candidate material for sodium-ion battery (SIB) anodes because of its higher electrical conductivity than monometallic sulfides owing to its lower bandgap. In this study, samples of bimetallic sulfide NixCo3-xS4 with tunable chemical Ni/Co components are successfully grown on graphene foam (GF), forming free-standing Chinese knot-like nanowires (NiCo2S4 NWs/GF) and Chinese lantern-like nanoarrays (CoNi2S4 NAs/GF). When evaluate as anodes for SIBs at 0.3-3.0 V in ether-based electrolytes, the NiCo2S4 NWs/GF electrodes offer superior rate performance and cycling stability than the CoNi2S4 NAs/GF electrodes. More specifically, the NiCo2S4 NWs/GF electrode has a high capacity of 650-556 mAh g(-1) at 0.1-2.0 A g(-1) and 457 mAh g(-1) after 200 cycles at 0.5 A g(-1) with a high initial coulombic efficiency (ICE) of 95.6%. And its rate performance outperforms most existing electrodes those contain NiSx, CoSx, or NiCo2S4. The excellent electrochemical performance of the NiCo2S4 NWs/GF electrode is attributed to its unique composition, smaller size, and porous nanowires that can reduce the diffusion length of e(-) and Na+, and enhance reaction kinetics. (C) 2021 Elsevier B.V. All rights reserved.