One-pot preparation of Ni2P nanoparticles anchored on N, P co-doped porous carbon nanosheets for high-efficiency lithium storage

Abstract Owing to high theoretical capacity and low voltage platforms as anode materials for lithium ion batteries (LIBs), transition metal phosphides (TMPs) have received considerable interest. However, the immense volume change during lithiation/delithiation process and poor electrical conductivity have greatly limited their applications. To overcome above shortcomings, constructing stable nanocomposites containing two-dimensional carbon and TMPs is extremely important. Herein, via chitosan as the carbon precursor, an original two-dimension nanocomposite of Ni2P nanoparticles immobilized N, P co-doped porous carbon nanosheets (Ni2P/NP-PC) through one-pot high temperature annealing process was proposed as anodes for LIBs. The microstructure verified that Ni2P/NP-PC had plentiful superiorities of numerous microporous channels, surface defects and large specific surface areas, which accelerated lithium ions migration and provided affluent active sites for lithium ions. Meanwhile, robust carbon nanosheets doped by N and P atoms increased ionic/electrical conductivity and released the volume expansion of Ni2P. Furthermore, the Ni2P/NP-PC exhibited exceptional specific capacity (879 mA h g−1 at 0.1 A g−1 after 100 cycles) and good cyclic performances (423.3 mA h g−1 at 2.0 A g−1 after 1700 cycles). It is expected that the facile method can be popularized to synthesize other TMPs composites for more energy storage systems.