Sodium-ion battery has been considered as an ideal alternative to lithium-ion battery due to the abundant resource of sodium. Hard carbon stands a good chance among most carbons to be the most promising anode material for sodium-ion battery because of its randomly oriented graphite layers. However, the disordered graphite layers display sluggish kinetics of sodium ions thus the high-rate capability of hard carbon in sodium-ion battery is still a big challenge. In this study, extremely ultrafast P-doped carbon nanosheet anode with graphene-like wrinkles and sheet thickness of ca. 8 nm for sodium-ion battery was synthesized by pyrolysis of coal pitch with the assistance of sodium hypophosphite. The ultrathin sheet structure and P-doped property could render pseudocapacitive behavior, as a result, the resultant carbon nanosheet anode delivers high-rate capacity and also the long-term cycling stability (i.e., a high reversible capacity of 189 mA h g⁻¹ at 2 A g⁻¹ after 500 cycles, and an extraordinarily high capacity of 80 mA h g⁻¹ at 20 A g⁻¹ after 10,000 cycles).

由于钠资源丰富，钠离子电池被认为是锂离子电池的理想替代品。由于其随机取向的石墨层，硬碳在大多数碳中很有可能成为最有前途的钠离子电池负极材料。然而，无序的石墨层表现出缓慢的钠离子动力学，因此硬碳在钠离子电池中的高倍率能力仍然是一个很大的挑战。在这项研究中，极快的 P 掺杂碳纳米片阳极具有类似石墨烯的皱纹和约 2 的片厚。在次磷酸钠的辅助下，煤沥青热解合成了 8 nm 钠离子电池。超薄的片状结构和 P 掺杂特性可以呈现赝电容行为，因此，所得碳纳米片负极提供高倍率容量和长期循环稳定性（即，189 mA h g ^-1 at的高可逆容量500 次循环后的2 A g ^-1，以及10,000 次循环后20 A g ^{-1 时}的 80 mAh g ^{-1 的}超高容量）。