Oxygen vacancy engineering of carbon-encapsulated (Co,Mn)(Co,Mn)2O4 from metal-organic framework towards boosted lithium storage

Abstract

Rational optimization of composition and structure is an engaging methodology to design prevailing anode materials for superior lithium storage to address their poor electronic conductivity and anomalous volumetric expansion upon cycling. Oxygen vacancy (OV) engineering can self-adaptively manipulate the active sites and electronic structure in transition metal oxides. Herein, a facile methodological strategy for MOF-derived oxygen vacancy-enriched (Co,Mn)(Co,Mn)2O4 encapsulated in carbon matrix (OV-CMO-600) is proposed to achieve boosted electronic conductivity and moderate volume expansion, facilitating exalted lithium storage performance. Systematically, the investigation of lithium storage kinetics endows that the enriched OV of OV-CMO-600 contributes to the boosted electronic conductivity and abundant active sites, further improving the charge diffusion kinetics and excellent rate performance. Moreover, the hollow structure and the carbonaceous layer render as an elastic buffer for mitigated volume fluctuation, thus contributing to cycling stability. Bestowed by the composition and structure compatibility, the OV-CMO-600 exhibits dazzling lithium storage performance along with distinguished cyclability (1624.5 mAh g−1 at 0.1 A g−1 up to 250 loops) and superior rate capability (331.4 mAh g−1 even at 5 A g−1). This work opens an avenue for meticulous engineering of MOF-derived vacancy-enriched metal oxides as advanced electrode material for energy storage application and development.