Ball-milled FeP/graphite as a low-cost anode material for the sodium-ion battery

Phosphorus is a promising anode material for sodium batteries with a theoretical capacity of 2596 mA h g(-1). However, phosphorus has a low electrical conductivity of 1 x 10(-14) S cm(-1), which results in poor cycling and rate performances. Even if it is alloyed with conductive Fe, it still delivers a poor electrochemical performance. In this article, a FeP/graphite composite has been synthesized using a simple, cheap, and productive method of low energy ball-milling, which is an efficient way to improve the electrical conductivity of the FeP compound. The cycling performance was improved significantly, and when the current density increased to 500 mA g(-1), the FeP/graphite composite could still deliver 134 mA h g(-1), which was more than twice the capacity of the FeP compound alone. Our results suggest that by using a low-energy ball-milling method, a promising FeP/graphite anode material can be synthesized for the sodium battery.