Transition metal sulfides (TMSs), owing to their high theoretical specific capacity, unique chemical and physical properties, were established as promising anode materials for potassium-ion batteries. However, the large volume expansion of the well-crystallized TMSs has an important influence on the structural stability during cycling. Herein, amorphous cobalt sulfide/N-doped carbon core/shell nanoparticles (ACSNPs) are obtained and work as preeminent anode and display excellent potassium storage performance. After 200 cycles, the ACSNPs show a reversible capacity of 253.4 mAh g−1 at 50 mA g−1, with a much better cycling stability than commercial cobalt sulfide. Amorphous cobalt sulfide wrapped in a N-doped flexible carbon shell not only suppresses the aggregation of small grains, but also confines the cobalt sulfide particles and inhibits large volume expansion during K-ion intercalation/deintercalation.

中文翻译：

---

无定形硫化钴/N掺杂碳核/壳纳米粒子作为钾离子存储负极材料

过渡金属硫化物（TMSs）由于其高理论比容量、独特的化学和物理性质，被确定为有前途的钾离子电池负极材料。然而，结晶良好的 TMS 的大体积膨胀对循环过程中的结构稳定性有重要影响。在此，获得了无定形硫化钴/N 掺杂的碳核/壳纳米粒子 (ACSNPs) 并作为卓越的阳极并显示出优异的储钾性能。200 次循环后，ACSNPs 在 50 mA g-1 下显示出 253.4 mAh g-1 的可逆容量，循环稳定性比商业硫化钴好得多。包裹在 N 掺杂柔性碳壳中的无定形硫化钴不仅抑制了小晶粒的聚集，