Heteroatoms in the carbon matrix are generally considered as active sites to enhance potassium storage capacity, while their adverse effects on ion batteries remain unclear. Herein, a series of sulfur doped carbon (SCDPx) with adjustable S content and crystallinity are accurately synthesized in the closed autoclave by controlling the ratios of precursors. Electrochemical measurements exhibit that heteroatom sulfur displays double‐edged electrochemical activities with a high initial potassium storage capacity but poor cycling stability for carbon anode. Combined with solid‐state nuclear magnetic resonance (NMR), catalytic tests, and various ex‐situ characterizations, it is demonstrated that abundant S in the carbon would not only form CSC bonds, acting as active sites to reversibly adsorb/desorb potassium ions for high capacity, but also significantly catalyze the reduction and decomposition of the electrolyte including KPF₆ and ethylene carbonate/diethyl carbonate (EC/DEC) to form thicker solid electrolyte interface (SEI) and degrade electrolyte, resulting in rapid capacity decay. As a result, the optimized sample (SCDP2) with the appropriate sulfur doping content exhibits the best electrochemical performance with high capacity (688.4 mA h g⁻¹ at 100 mA g⁻¹), long‐term cycling stability (198.4 mA h g⁻¹ at 2000 mA g⁻¹ after 10 000 cycles), and excellent rate capability (238.8 mA h g⁻¹ at 5000 mA g⁻¹).

中文翻译：

---

揭示碳质材料中杂原子硫的双刃行为，以平衡钾存储容量和稳定性

碳基体中的杂原子通常被认为是增强钾储存能力的活性位点，但它们对离子电池的不利影响仍不清楚。在此，通过控制前驱体的比例，在密闭高压釜中精确地合成了具有可调节的S含量和结晶度的一系列硫掺杂碳（SCDP x）。电化学测量表明，杂原子硫表现出双刃电化学活性，具有较高的初始钾存储容量，但对碳阳极的循环稳定性较差。与固态核磁共振（NMR），催化测试，以及各种易地表征结合中，证明的是，在碳丰富S。将不仅C型小号C键可作为活性位点可逆地吸附/解吸钾离子以实现高容量，同时还显着催化包括KPF ₆和碳酸亚乙酯/碳酸二乙酯（EC / DEC）在内的电解质的还原和分解，从而形成较厚的固体电解质界面（ SEI）并降解电解质，导致容量快速衰减。其结果，最优化的样品（SCDP2）与合适的硫掺杂含量表现出具有高容量（688.4毫安汞柱电化学性能最好^-1在100mA克^-1），长期循环稳定性（198.4毫安汞柱^-1在2000毫安克^-1 10 000次循环后），以及优异的倍率性能（238.8毫安汞柱^-1在5000毫安克^-1）。