软@硬复合炭结构设计及其协同电化学储钾

软@硬复合炭结构有助于协同改善炭负极材料的电化学储钾性能，但目前对不同复合结构对电化学储钾性能的影响规律仍缺乏系统研究。有鉴于此，将罗丹宁和嵌段共聚物F127作为硬炭前驱体，煤沥青热挥发份作为软炭前驱体，通过共炭化与气相沉积的协同使用，开发硬炭、软/硬三维杂化炭结构、软炭壳@硬炭核复合结构，并研究3种结构对电化学储钾性能的影响。软炭壳@硬炭核复合材料具有高可逆容量(0.05 A·g^-1下容量为365 mA·h·g^-1)、高循环稳定性(100圈循环后容量保持率为80%)、高倍率性能(1 A·g^-1下容量为177 mA·h·g^-1)的特征。硬炭核丰富的缺陷活性位点可提高复合材料储钾容量。软炭壳的涡轮碳结构可覆盖硬炭表面缺陷，促进钾离子去溶剂化嵌入以改善循环稳定性。此外，高导电性软炭壳可改善电荷交换，进而提高复合材料的倍率性能并缓解电压滞后。得益于软炭与硬炭复合结构的协同储钾机制，软炭壳@硬炭核复合材料表现出明显优于硬炭的电化学储钾性能。

Hard@soft composite carbon anodes towards synergistic potassium storage

Hard@soft composite carbon can improve the potassium storage performance synergistically by combining the advantage of hard carbon and soft carbon. But the potassium storage mechanism of different composite structure is lack. Here, rhodanine and F127 were used as the precursor of hard carbon, and the volatile matter of coal tar pitch was used as the precursor of soft carbon. Hard carbon, soft/hard hybrid carbon and soft carbon shell@hard carbon core composite were fabricated using co-carbonization and chemical vapor deposition. When used as the anode materials of potassium-ion battery, soft carbon shell@hard carbon core composite possesses high reversible capacity (365 mA·h·g?1 at 0.05 A·g?1), high cyclic stability (80% after 100 cycles), and excellent rate performance (177 mA·h·g?1 at 1 A·g?1). It can be ascribed to the abundance of active sites of hard carbon and the coating of soft carbon on the defect sites at the surface of hard carbon. Moreover, the soft carbon can improve the conductivity of the composite, which can enhance the rate performance of composite anode and release the voltage hysteresis. Benefiting from the synergistic potassium storage, soft carbon shell@hard carbon core composite anode shows much better performance than hard carbon anode.