Freestanding hierarchically 3D porous Co2P-Co@C films with superior electrochemical kinetics for enhanced lithium-ion batteries anode performance

Abstract Rapid electrochemical dynamics and stable structures are critical for the practical application of transition metal phosphides (TMPs)-based lithium-ion batteries anode materials. Herein, a facile strategy is developed to construct a self-supporting 3D porous dual-phase Co2P-Co film covered by a carbon layer (Co2P-Co@C) based on the bubble template method electrodeposition of CoP film, glucose adsorption, and annealing treatment. The electron/ion transport is improved due to a large number of active sites and increased conductivity of Co2P by Co and carbon coating. Meanwhile, the volume expansion is alleviated, benefiting from the sufficient space provided by porous structure and the protection of carbon layer. Consequently, the Co2P-Co@C film exhibits high reversible capacity (823 mAh g-1 at 0.2 A g-1 after 100 cycles), excellent rate capability (506 mA h g-1 at 4 A g-1) and outstanding long-term cycling stability (567.9 mAh g-1 at 2 A g-1 after 400 cycles).