CoSe nanoparticles in-situ grown in 3D honeycomb carbon for high-performance lithium storage.

Although transition metal selenides are considered to be extremely promising anode materials for lithium-ion batteries (LIBs), severe volume changes and low electronic conductivity are their huge and unavoidable challenges. To solve these problems, CoSe nanoparticles in-situ grown on the inner surface of every macropore of 3D honeycomb C is successfully synthesized by three simple steps: dense assembling of polystyrene spheres, calcination and gaseous selenylation. The sizes of CoSe and honeycomb pores are 10-15 nm and 190 nm, respectively. The content of CoSe is 72 wt%. This unique architecture guarantees high electrochemical activity, rapid reaction kinetics and excellent structural stability of CoSe, as identified by cycling and rate performance measurements, various electrochemical kinetics analyses and ex-situ characterization of the cycled electrode material. As a result, the CoSe@honeycomb C anode exhibits extraordinary cycling performance (823.5 mAh g after 200 cycles at 0.5 A g, 610.1 mAh g after 250 cycles at 2 A g, 247 mAh g after 1500 cycles at 5 A g) and exceptional rate capability (261.9 mAh g at 10 A g, 1491.4 mAh g at 0.1 A g), demonstrating that it is a potential anode material for high-performance LIBs.