Solid CoZn glycerate template-based engineering of yolk-shell bimetallic sulfides heterostructures microspheres confined in N, S-doped carbon as anode materials for lithium/sodium-ion batteries

Abstract

Realization of an anti-pulverization electrode structure is extremely important for developing high-performance Li/Na storage, and yet this technology is still challenging. Herein, the yolk-shell Co9S8/ZnS heterostructure encapsulated by N, S-doped carbon (YS Co9S8/ZnS@SNC) is successfully synthesized from solid CoZn glycerate microsphere for the first time and utilized as the anode materials for Li/Na storage. Consequently, the optimized YS Co9S8/ZnS@SNC electrode exhibits superior Li/Na storage performance, involving excellent reversible capacity and outstanding rate capability with high specific capacity. The superior performances of the electrode are attributed to the two factors: ⅰ) The YS structure can not only accommodate the volume variation effectively to resist pulverization during Li/Na-ions insertion/extraction, but also enable sufficient contact of Co9S8/ZnS and electrolyte to improve electron/ion transportation in the electrode; ⅱ) in-situ constructed Co9S8/ZnS heterostructure and its surface coated SNC layer can provide a high efficient transfer path for electrons. Density functional theory calculations further confirm the excellent conductivity of the Co9S8/ZnS and its delocalized electron distribution. Importantly, the strategy provides a new opportunity to realize high-performance energy storage from various glycerate template-based transition metal compounds.