Novel Ni/Ni2P@C hollow heterostructure microsphere as efficient sulfur hosts for high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur (Li-S) batteries present the potential viable rechargeable batteries in the field of energy-storage devices. However, the migration of lithium polysulfides (LiPSs) and slow electrochemical reaction kinetics are still the intractable problems on the development of Li-S batteries. Herein, novel Ni/Ni2P@C hollow heterostructure microsphere, as the functional sulfur host material, is prepared by a facile approach. The study found that the novel hollow microsphere composed of porous carbon layer alleviates the volume expansion effect and effectively improves the electron transport during cycling process. In addition, the Ni/Ni2P heterostructure wrapped in carbon layer not only improves the adsorption of LiPSs, but also catalyzes their conversion reactions. Therefore, Li-S batteries with the S/Ni/Ni2P@C electrode exhibit high discharge capacity of 1187.3 mAh g−1 at 0.2 C in the first cycle, notable rate capability of 716.9 mAh g−1 at 3 C and outstanding reversible capacity of 636.6 mAh g−1 over the 500 cycles at 1 C. Owing to these excellent electrochemical performances, the Ni/Ni2P@C hollow heterostructure microsphere has promising applications for Li-S batteries.