NiO nanocrystals encapsulated into a nitrogen-doped porous carbon matrix as highly stable Li-ion battery anodes

Though the carbon matrix is extensively investigated to enhance the electrochemical performances of metal oxides for lithium-ion batteries (LIBs), it is still difficult to expose the whole active sites in the electrode material to participate in electrochemical reactions. Herein, we report a facile MOF-derived strategy for the controlled synthesis of a hybrid structure with NiO nanocrystals uniformly distributed into nitrogen-doped porous carbon matrix (NiO@N-C). In this strategy, the simultaneously generated nitrogen-doped porous carbon matrix can confine the further growth of the resulting NiO nanocrystals during the carbonization process, in which the ultrafine particle sizes of NiO can shorten ion diffusion length and provide abundant exposed active sites for lithium-storage, while the carbon matrix can function as a buffer layer to alleviate the volume expansion. Benefiting from the advantages of the structural features and porous carbon matrix, NiO@N-C delivers a large reversible capacity of 1373 mAh g(-1) at 100 mA g(-1) after 200 cycles and a remarkable cycling stability up to 1000 cycles at 1 A g(-1) with a capacity of 877 mAh g(-1), suggesting its potential as an anode material for lithium-ion batteries. (C) 2020 Elsevier B.V. All rights reserved.