Biochar-Derived Hierarchical Porous Carbon as Tellurium Host for High-Performance Potassium-Tellurium Batteries

Graphical The Te@PC-MS composites based on the biomass carbon from mangosteen shell exhibit the superior K + -storing performances. The existence of abundance of micro-/mesopores in the hierarchical structure could effectively alleviates volume fluctuance during K-Te battery operation. Potassium-ion battery is promising for its high abundance and low redox potential. As a conversion cathode, Te possesses high conductivity and theoretical volumetric capacity to couple with potassium. The stubborn issues of K-Te battery focus on the large volume change and rapid structure degradation of Te. Herein, we produce biomass carbon from mangosteen shell in a facile method, and obtain a hierarchical porous host with abundance of micropores and mesopores, which is obviously beneficial for hosting Te during K + storage in K-Te battery. The specific capacity reach to 560 mAh g −1 in the initial cycle at 0.1 A g −1 , and remained 83.8 % after 200 cycles. Impressively, at a high current density of 2.0 A g −1 , the specific capacity still remained 62.6 % after 5000 cycle. These results endow such strategy an efficient way for the development of K-Te batteries.