Hollow CoP nanoparticles embedded in carbon nanotube arrays as sodium ion battery anode with superior performance

Abstract We report a facile strategy to prepare carbon nanotubes embedded with hollow CoP nanoparticles arrays (H-CoP-NPs@CNTs) on flexible carbon cloth through hydrothermal synthesis, carbothermal reduction and phosphorization. The unique H-CoP-NPs@CNTs as free-standing sodium ion battery anodes exhibit remarkable electrochemical performances a specific capacity of 965.6 mA h g−1 for the 1st cycle and 63% retained capacity after rates test and 100 cycles at 100 mA g-1. The capacity retention rate is as high as 94.3% after different current sweeps. The excellent electrochemical performance can be attributed to the unique 1D hybrids nanoarrays structures, in which the pore inside and between hollow CoP nanoparticles provide more free spaces and active sites for favorable Na+ insertion/extraction, and the CNTs nanoarrays on flexible carbon cloth are able to improve the conductivity and maintain the structural integrity. Moreover, the 1D hybrids network also makes it favorable rapid ion/electron transport and enhanced rate performance.