Stable Na/K-S Batteries with Conductive Organosulfur Polymer Microcages as Cathodes.

Na-S and K-S batteries, with high-energy density, using naturally more abundant and affordable metals compared with rare resources like Li, Co, and Ni elements, have inspired intense research interest. However, the sulfur cathodes for Na/K storage are plagued by soluble polysulfide shuttling, larger volumetric deformation, and sluggish redox kinetics. Here, we report that a conductive organosulfur polymer microcage, fabricated facilely with the microbe and elemental sulfur as precursors, can effectively address these issues for stable high-capacity Na-S and K-S batteries.

Shell Modulation of Hollow Metal Sulfide Nanocomposite for Stable Potassium Storage at Room and High Temperature.

The large size of K-ion makes the pursuit of stable high-capacity anodes for K-ion batteries (KIBs) a formidable challenge, particularly for high temperature KIBs as the electrode instability becomes more aggravated with temperature climbing. Herein, we demonstrate that a hollow ZnS@C nanocomposite (h-ZnS@C) with a precise shell modulation can resist electrode disintegration to enable stable high-capacity potassium storage at room and high temperature. Based on a model electrode, we identify an interesting structure-function correlation of the h-ZnS@C: with an increase in the shell thickness, the cyclability increases while the rate and capacity decrease, shedding light on the design of high-performance h-ZnS@C anodes via engineering the shell thickness.