In Situ Mechanistic Insights into the Divergent Electrochemical Behaviors of Li, Na, and K in Metal Sulfur Batteries
Xinting Cao, Guoquan Sun, Ze Hua, Lei Zhou, Peifeng Gao, Li Yan, Lixia Bao, Xiaoxue Chang, Leining Zhang, Guoqiang Tan, Lihua Wang, Xintao Zuo, Ruiwen ShaoAbstract
Metal–sulfur batteries are promising candidates for next-generation energy storage, yet the origins of their distinct reaction behaviors remain elusive. Here, we employ a noncatalytic vapor-grown carbon fibers/sulfur (VGCF/S) interface to regulate sulfur electrochemistry. In situ TEM reveals highly reversible two-step redox reactions and rapid reaction-front propagation in Li–S nanobatteries. Coin-cell measurements further show reversible cycling and rate capability for Li–S under specific testing conditions. DFT calculations in idealized graphitic and sulfur–carbon environments provide a qualitative comparison of alkali-species-dependent migration. The observed divergence may reflect coupled contributions from alkali-species transport, interfacial processes, electrolyte-dependent sulfur-redox pathways, and product evolution. This work highlights noncatalytic interfaces as a platform for probing sulfur electrochemistry.