High lithium storage performance of CoO with a distinctive dual-carbon-confined nanoarchitecture

Herein, a distinctive dual-carbon-confined nanoarchitecture, composed of an inner highly conductive, robust carbon nanotube (CNT) support and outer well-designed porous carbon (PC) coating, was demonstrated to efficiently improve the electrochemical properties of CoO nanoparticles for the first time, and the CoO nanoparticles were confined between the CNTs and porous carbon. The well-designed porous carbon coating showed significant superiority compared to common non-porous carbon coatings, due to its distinctive characteristics such as high flexibility, rich free space and open tunnel-like structure. Therefore, the synergistic effects of the CNT core and the porous carbon sheath endowed the CoO-based composite (CNTs@CoO@PC) with improved electrochemical reaction kinetics, large pseudocapacitive contribution and superior structural stability. As a result, the CNTs@CoO@PC showed outstanding performance with 1090, 571 and 242 mA h g^-1 at 200, 1000 and 5000 mA g^-1 after 300, 600 and 1000 cycles, respectively. Furthermore, this strategy may be used to improve other metal oxide anode materials for lithium storage.