Sulfur‐Grafted Hollow Carbon Spheres for Potassium‐Ion Battery Anodes

• DOI: 10.1002/adma.201900429
• Publication Date: 2019-06-03T09:37:14Z
• Authors: Jia Ding; Hanlei Zhang; Hui Zhou; Jun Feng; Xuerong Zheng; Cheng Zhong; Eunsu Paek; Wenbin Hu; David Mitlin
• Keywords: Potassium-ion battery; Carbon fibers

Sulfur-rich carbons are minimally explored for potassium-ion batteries (KIBs). Here, a large amount of S (38 wt%) is chemically incorporated into carbon host, creating sulfur-grafted hollow spheres (SHCS) KIB anodes. The SHCS architecture provides combination nanoscale (≈40 nm) diffusion distances and CS chemical bonding to minimize cycling capacity decay Coulombic efficiency (CE) loss. exhibit reversible 581 mAh g-1 (at 0.025 A ), which the highest reported any carbon-based anode. Electrochemical analysis S-free baseline demonstrates that both matrix sulfur species highly electrochemically active. also show excellent rate capability, achieving 202, 160, 110 at 1.5, 3, 5 , respectively. electrode maintains 93% from 5th 1000th cycle 3 with steady-state CE being near 100%. Raman indicates breakage SS bonds upon potassiation 0.01 V versus K/K+ . galvanostatic intermittent titration technique (GITT) voltage-dependent K+ coefficients range 10-10 10-12 cm2 s-1 depotassiation, approximately five times higher coefficient former.