Soft carbons (SCs) have become a promising anode for potassium ion batteries (PIBs). However, it is challenging to maintain high capacity and long cycle life at rapid charge/discharge rate due to the sluggish insertion/deinsertion of K⁺. To solve this problem, the morphology of the SCs was regulated by using pitches with different chemical structures. The results showed that the chemical structure of the pitch characterized by less long aliphatic chains led to the largest average distance between polycyclic aromatic nuclei, which caused mild condensation of polycyclic aromatic nuclei and thus the formation of lamellar structures. Abundant short chains of the pitch ignited violent cyclization and aromatization and the shortened average distance, inducing violent condensation to generate the bulk structures. The cyclopenta-fused rings and aromatic methyl groups of the pitch minimized the average distance, which also built the bulk structures. More exposed defect-edge sites and larger active surface of the lamellar SC contributed to the adsorption of K⁺ and improved reaction kinetics. When the current density increased to 3C,bulk structures did not work while the lamellar still remained high reversible capacity of 160.9 mAh g⁻¹ after 1000 cycles. These findings paved a new way for the design of SCs at the molecular level to satisfy high electrochemical performance at high charge/discharge rate.

软碳 (SC) 已成为钾离子电池 (PIB) 的有前途的阳极。然而，由于 K ^{+的缓慢插入/脱嵌，在快速充电/放电速率下保持高容量和长循环寿命具有挑战性}. 为了解决这个问题，通过使用具有不同化学结构的沥青来调节 SC 的形态。结果表明，沥青的化学结构以较短的脂肪链为特征，导致多环芳核之间的平均距离最大，从而导致多环芳核温和缩合，从而形成层状结构。丰富的沥青短链引发剧烈的环化和芳构化以及缩短的平均距离，引起剧烈的缩合以产生块状结构。沥青的环戊稠合环和芳族甲基最小化了平均距离，这也构建了块状结构。更多暴露的缺陷边缘位点和层状 SC 的更大活性表面有助于 K ^+的吸附和改进的反应动力学。当电流密度增加到3C时，块状结构不起作用，而层状结构在1000次循环后仍保持160.9 mAh g ^{-1的高可逆容量。}这些发现为在分子水平上设计 SC 以满足高充电/放电速率下的高电化学性能开辟了一条新途径。