Remarkable enhancement in the electrochemical activity of maricite NaFePO4 on high-surface-area carbon cloth for sodium-ion batteries

The electrochemical reversibility of maricite NaFePO4 is highly dependent on the rational design of the nanostructure. We propose, for the first time, an effective strategy of applying an acid-etched carbon cloth (eCC) as the substrate to be loaded with NaFePO4@C and significantly enhance the electrochemical activity of the maricite. The electrochemical test results show that the NaFePO4@C loaded on eCC exhibits a much higher reversible capacity (142 mAh g−1 at 0.1 C) than that (107 mAh g−1 at 0.1 C) of the material loaded on an Al current collector. Moreover, compared to that of the untreated carbon cloth (CC), NaFePO4@C loaded on eCC shows a superior rate performance and ultralong cycling lifetime at high mass loading levels. The excellent electrochemical performance of the NaFePO4@C-eCC electrode benefits from the regular grooves on the surface of the eCC, which provide a significantly larger surface area that is favorable to NaFePO4@C strongly and uniformly binding onto the carbon fibers. The self-supporting electrode configuration, that is, without the addition of an inactive binder and conductive additives, facilitates fast ion/electronic transport and reduces the aggregation of the NaFePO4@C particles. This work is expected to provide a new route for achieving high electrochemical activity in NaFePO4.