Heteroatoms introduction via Temperature-Differential doping strategy achieves Long-Cycle-Life NiCoMo-P LDH cathode for rechargeable Chloride-Ion battery

Abstract

As one of the most promising insertion-type cathodes for the novel chloride ion batteries (CIBs), layered double hydroxides (LDHs) materials have been extensively investigated in the recent years as the typical inorganic anion conductors. Nevertheless, poor intrinsic conductivity and sluggish reaction kinetics of LDHs challenge directly the further development in terms of chloride storage capacity and cycling life. Herein, phosphorus doped NiCoMo LDH in chloride form (NiCoMo-P LDH) is demonstrated as a high performance cathode for CIB. The unique temperature-differential doping methode allows P heteroatoms to incorporate into the metal–oxygen octahedral matrix of LDHs host layers, which have no effect on the entire crystal structure of 2D LDHs and the stable presence of interlayer Cl ions. By combining the advanced spectroscopy techniques and DFT theoretical calculations, abundant vacancies are proved to be introduced into NiCoMo-P LDH and both the conductivity and chloride-ion diffusion rate are significantly improved, providing more active adsorption sites for electrochemical reactions, thus strengthening the Cl ions storage performance with a stable discharge capacity of 150.2 after 800 charging/discharging processes at a current density of 300 mA g−1. This study presents a facile strategy for the rational doping of hetero-anions in LDHs materials for CIBs at relative low-temperature, which can also be adopted in other types of halide-ion-based rechargeable batteries.