Toward high-performance Li storage anodes: design and construction of spherical carbon-coated CoNiO2 materials

CoNiO2 nanosheets were prepared by a simple hydrothermal process, and then the spherical CoNiO2@C micro-nano structures composed of nanoparticles were designed by morphology reshaping for the first time. The results show that the carbon coating changes the morphology of CoNiO2, and the CoNiO2@C composite shows porous microsphere structure consisted of nanoparticles. The porous structure combined with highly conductive carbon shell indicates an improved electronic conductivity and charge transfer. The carbon shell decreases the charge-transfer resistance of CoNiO2, and thus enhances the kinetic performances. The pristine CoNiO2 and CoNiO2@C (3, 5, and 10 wt%) composites deliver charge/ discharge capacities of 511.7/526.9, 811.3/826.3, 997.1/1013.1, and 1216.1/1241.8 mAh g(-1) at 500 mA g(-1) after 200 cycles, respectively. The carbon coating improves the reversible capacity, rate capability, and cycle performance of CoNiO2, especially at high rates. The improved rate performance, excellent cycle performance, and high kinetic performances are ascribed to the elaborate design of architecture and composition. Hence, such porous CoNiO2@C microsphere consisted of nanoparticles can be regarded as promising candidates as anode materials for lithium-ion battery. (C) 2020 Elsevier Ltd. All rights reserved.