Oxygen-deficient and orderly mesoporous cobalt oxide nanospheres for superior lithium storage

Lithium-ion batteries (LIBs) dominate the current electrical and electronic markets. However, the energy density that approaches the theoretical limit for conventional LIBs struggles to meet the future energy demand. Herein,5 oxygen-deficient cobalt oxide nanospheres in three-dimensional ordered mesoporous architecture (3DOM Co3O4-X) are developed via a simple nanocasting method, which serve as advanced anode materials for superior lithium storage. The unique highly porous and robust construction facilitates the mass transfer, restrains the volume expansion, and exposes vast interfaces for reversible lithiation/delithiation, while the oxygen vacancies in Co3O4-X lattice promote the electron/ion conductions and enrich the active sites for conversion reactions. Benefiting from these synergistic attributes, the 3DOM Co3O4-X electrodes retain a highly reversible capacity of 629.1 mA h g(-1) after 1000 cycles at 2 A g(-1), which significantly outperform the Co3O4 nanoparticle counterpart. This work demonstrates a highly promising material advancement combining architecture and defect engineering towards high-performance LIBs. (C) 2021 Elsevier B.V. All rights reserved.