Effect of Cobalt on Lifetime of Sb 4 O 5 Cl 2 -Graphene Anode in Chloride-Ion Batteries.

Anode materials based on metal oxychlorides hold promise in addressing electrode dissolution challenges in aqueous-based chloride ion batteries (CIBs). However, their structural instability following chloride ion deintercalation can lead to rapid degradation and capacity fading. This paper investigates a cobalt-doped Sb 4 O 5 Cl 2 -graphene (Co-Sb 4 O 5 Cl 2 @GO) composite anode for aqueous-based CIBs. It exhibits significantly enhanced discharge capacity of 82.3 mAh g -1 after 200 cycles at 0.3 A g -1 ; while, the undoped comparison is only 23.5 mAh g -1 in the same condition. It also demonstrated with a long-term capacity retention of 72.8 % after 1000 cycles (65.5 mAh g -1 ) and a favorable rate performance of 25 mAh g -1 at a high current density of 2 A g -1 . Undertaken comprehensive studies via in-situ experiments and DFT calculations, the cobalt (Co) dopant is demonstrated as the crucial role to enhance the lifetime of Sb 4 O 5 Cl 2 -based anodes. It is found that, the Co dopant improves electronic conductivity and the diffusion of chloride ions beside increases the structural stability of Sb 4 O 5 Cl 2 crystal. Thus, this element doping strategy holds promise for advancing the field of Sb 4 O 5 Cl 2 -based anodes for aqueous-based CIBs, and insights gain from this study also offer valuable knowledge to develop high-performance electrode materials for electrochemical deionization.