As emerging energy storage systems, potassium-ion batteries (PIBs) are suitable for grid-scale energy storage application due to the abundant potassium resources and low cost. It is crucial to achieve fast-charging PIBs. However, as the most promising anode candidate, graphite still faces setbacks in achieving fast charging due to poor kinetic issue. Herein, modified graphite (MG) is synthesized to realize the fast potassium ion storage. Benefiting from the enlarged graphitic space combined with unique porous microstructure, MG exhibits outstanding electrochemical performance. The optimized MG anode delivers a specific capacity of 115 mAh g⁻¹ at 4 A g⁻¹ and excellent cycling stability of 1500 cycles at 1 A g⁻¹. Moreover, the full cell assembled with MG anode and Prussian Blue (PB) cathode exhibits a capacity retention of 75% after 20000 cycles at the current density of 1 A g⁻¹. The excellent electrochemical performance is further demonstrated to be associated with dominant pseudo-capacitance behavior, i.e. surface or near-surface reversible redox reactions, which are less affected by solid electrolyte interface (SEI) than intercalation reactions. Our work proposes a strategy to optimize graphitic anode materials by regulating the microstructure and may provide insight into the synthesis of high rate carbon-based anode materials for PIBs.

作为新兴的储能系统，钾离子电池（PIBs）由于钾资源丰富且成本低，适合于电网规模的储能应用。实现快速充电的 PIB 至关重要。然而，作为最有前途的负极候选者，由于动力学问题，石墨在实现快速充电方面仍然面临挫折。在此，合成改性石墨（MG）以实现钾离子的快速储存。受益于扩大的石墨空间和独特的多孔微结构，MG 表现出出色的电化学性能。优化的 MG 负极在 4 A g ^{-1 下}提供 115 mAh g ^-1的比容量和在 1 A g ^-1下 1500 次循环的优异循环稳定性. 此外，由MG阳极和普鲁士蓝(PB)阴极组装的全电池在1 A g ^-1的电流密度下在20000次循环后显示出75%的容量保持率。优异的电化学性能被进一步证明与主要的赝电容行为有关，即表面或近表面可逆氧化还原反应，与嵌入反应相比，受固体电解质界面 (SEI) 的影响较小。我们的工作提出了一种通过调节微观结构来优化石墨负极材料的策略，并可能为 PIB 的高倍率碳基负极材料的合成提供见解。