CTAB-modified Ni2P@ACNT composite with enhanced supercapacitive and lithium/sodium storage performance

Transition metal phosphides (TMPs) are considered as one class of excellent energy storage materials. However, serious volume variation and agglomeration during charging and discharging hamper their development. In this paper, monodispersed Ni2P nanoparticles have been loaded on acid treated carbon nanotubes (Ni2P @ACNT(CTAB)) via a cationic surfactant-assisted hydrothermal synthesis approach. The resultant electrode can be used both in supercapacitors (SCs) and lithium/sodium-ion batteries (LIBs/SIBs) with excellent energy storage performance. Especially, the three-dimensional and omnidirectional conducting network of CNTs can provide open highways for electron/ion transport and promote electrode reaction kinetics. As a battery-type electrode for SCs, Ni2P@ACNT(CTAB) electrode has demonstrated a remarkable capacitance of 328.0 F.g(-1) at 1 A.g(-1). As an anode for LIBs, a significant capacity of 1475 mAh.g(-1) can be delivered at 0.2 A.g(-1) after 320 cycles, and a high capacity of 509.8 mAh.g(-1) is achieved at 8 A.g(-1). As an anode for SIBs, a significant capacity of 150.1 mAh.g(-1) can be delivered at 0.1 A.g(-1) after 100 cycles, and a high capacity of 104.8 mAh.g(-1) is achieved at 4 A.g(-1). The reaction mechanism is analyzed by Ex-situ XRD patterns. This design provides obvious advantages for the application of Ni2P based electrodematerials for hybrid supercapacitors and batteries.