Hollow Nanotubes of N-Doped Carbon on CoS

Low-cost, single-step synthesis of hollow nanotubes of N-doped carbon deposited on CoS is enabled by the simultaneous use of three functionalities of polyacrylonitrite (PAN) nanofibers: 1)a substrate for loading active materials, 2)a sacrificial template for creating hollow tubular structures, and 3)a precursor for insitu nitrogen doping. The N-doped carbon in hollow tubes of CoS provides a high-capacity anode of long cycle life for a rechargeable Li-ion or Na-ion battery cell that undergoes the conversion reaction 2A(+)+2e(-)+CoSCo+A(2)S with A=Li or Na.