One-step synthesis of hollow spherical Co/Ni hydroxides as multifunctional polysulfide mediators to steer sulfur redox kinetics for high performance lithium–sulfur batteries

Abstract

Accelerating the kinetics of sulfur redox reactions and suppressing the shuttle effect of lithium polysulfides (LiPSs) have been considered as the fundamental route to boost the performance of lithium–sulfur batteries (LSBs). In this study, a one-step facile method has been developed to controllably synthesize a porous H-Co_xNi_1−x sulfur host. Both the experimental analysis and theoretical calculations illustrated that the modulated electronic structure and d-orbitals of the sulfur host are beneficial to regulate the electronic coupling interactions between the LiPSs and sulfur hosts, thus optimizing the binding energies between the reactants and the catalysts. The synergistic catalysis effect of Co and Ni further promotes the kinetics for sulfur redox reactions. Benefiting from the above characteristics, H-Co_0.4Ni_0.6 displayed an excellent adsorption-catalysis performance for LiPSs and a high reversible capacity of 696.1 mA h g⁻¹ was achieved after 250 cycles. The present study provides a novel strategy to boost the performance of LSBs, and offers a new insight into how the composition and electronic structure influence the adsorption-catalysis performance.