Low-Carbon and Nanosheathed ZnCo2O4 Spheroids with Porous Architecture for Boosted Lithium Storage Properties.

Multielectronic reaction electrode materials for high energy density lithium-ion batteries (LIBs) are severely hindered by their inherent sluggish kinetics and large volume variations, leading to rapid capacity fade. Here, a simple method is developed to construct low-carbon and nanosheathed ZnCo2O4 porous spheroids (ZCO@C-5). In this micro/nanostructure, an ultrathin amorphous carbon layer (~2 nm in thickness) is distributed all over the primary nanosized ZCO particles (~20 nm in diameter), which finally self-assembles into porous core (ZCO)-shell(carbon) micron spheroids. The nanoencapsulation and macro/mesoporous architecture can not only provide facile electrolyte penetration and rapid ion/electron transfer but also better alleviate volumetric expansion effect to avoid pulverization of ZCO@C-5 spheroids during repeat charge/discharge processes. As expected, the three-dimensional porous ZCO@C-5 composites exhibit high reversible capacity of 1240 mAh g-1 cycle at 500 mA g-1, as well as excellent long-term cycling stability and rate capability. The low-carbon and nanoencapsulation strategy in this study is simple and effective, exhibiting great potential for high-performance LIBs.