Tellurium: A High‐Volumetric‐Capacity Potassium‐Ion Battery Electrode Material
Shuai Dong, Dandan Yu, Jie Yang, Li Jiang, Jiawei Wang, Liwei Cheng, Yan Zhou, Honglei Yue, Hua Wang, Lin Guo
Abstract
Abstract Currently, exploring high‐volumetric‐capacity electrode materials that allow for reversible (de‐)insertion of large‐size K + ions remains challenging. Tellurium (Te) is a promising alternative electrode for storage of K + ions due to its high volumetric capacity, confirmed in lithium‐/sodium‐ion batteries, and the intrinsic good electronic conductivity. However, the charge storage capability and mechanism of Te in potassium‐ion batteries (KIBs) have not been unveiled until now. Here, a novel K–Te battery is constructed, and the K + ‐ion storage mechanism of Te is revealed to be a two‐electron conversion‐type reaction of 2K + Te ↔ K 2 Te, resulting in a high theoretical volumetric capacity of 2619 mAh cm −3 . Consequently, the rationally fabricated tellurium/porous carbon electrodes deliver an ultrahigh reversible volumetric capacity of 2493.13 mAh cm −3 at 0.5 C (based on Te), a high‐rate capacity of 783.13 mAh cm −3 at 15 C, and superior long‐term cycling stability for 1000 cycles at 5 C. This excellent electrochemical performance proves the feasibility of utilizing Te as a high‐volumetric‐capacity active material for storage of K + ions and will advance the practical application of KIBs.