Pyrolysis of coal pitch-infused melamine foam to construct N-doped carbon anodes for high-performance sodium-ion battery

Coal pitch is a promising precursor to construct carbonaceous anode for lithium-ion battery and sodium-ion battery because of its rich natural resource and low development cost. Nonetheless, quite unsatisfactory Na-storage performance had been gained using the pitch-based carbon anodes obtained by direct pyrolysis of pitch where the high graphitization degree nature of the carbon would result in a small interlayer distance. In this study, low-graphitized pitch-based carbon with N-containing functional groups for sodium ion batteries was successfully constructed by ferric nitrate-assist carbonization of coal pitch-infused melamine foam. Melamine foam skeleton can effectively reduce the graphitization of the final carbon material while the ferric nitrate can adjust the pore structure of the carbon framework, so that the obtained N-doped carbon has a larger layer spacing distance which makes it easier to insert and extract the sodium ions into and out the carbon structure during the discharge–charge process. When evaluated as sodium ion batteries anodes, the obtained carbon material presents a high reversible storage capacity (111 mA h g−1) and stable cyclability (1000 cycles at 8.0C rate, nearly 3.0 A g−1).