A Se-hollow porous carbon composite for high-performance rechargeable K–Se batteries

In this study, a novel hollow carbon matrix was designed and prepared using a facile NaCl crystal template for the effective encapsulation of Se. This superior carbon electrode plays a significant role in facilitating sufficient energy storage and conversion of Se-based cathode materials. A large specific surface area of 416 m2 g−1 was obtained, and the matrix provided numerous hollow spheres for the storage of Se. The thermogravimetric analysis and electrochemical results show that the as-prepared Se-hollow porous carbon composite with an ideal Se content of 42% can make excellent capacity contribution. The hollow porous structure not only effectively accommodates the volumetric expansion during the discharge–charge process but also makes the composite have a good contact with the electrolyte. In addition, the 3D open framework structure can be conducive to fast electron transportation. As a result, the Se-hollow porous carbon composite exhibited outstanding electrochemical performance when evaluated as a cathode material for rechargeable K–Se batteries.