Universal low-temperature and template-free synthesis of sponge-like porous micron-sized elemental materials for high-performance lithium/potassium storage

Abstract

Interconnected porous micron-sized materials can effectively enhance the ion transfer kinetics and structural stability, thus improving their rate capability and long-term lifespan, and maintaining high volumetric performance, but developing a universal and low-temperature method for the large-scale synthesis of porous materials remains a formidable challenge. Herein, we develop a universal low-temperature and template-free strategy to fabricate a series of sponge-like, interconnected porous micron-sized elements (e.g., Se, Te, Sb) through H2O2-assisted water bath. The formation mechanism of porous structure is demonstrated, originating from the non-homogeneous and continuous corrosion due to the preferential intergranular corrosion of polycrystalline particles and the soluble reaction products that do not passivate the corrosion interface. The as-obtained sponge-like porous elements present large reversible gravimetric and volumetric capacities and long stable lifespans. Specifically, the porous Te electrode delivers a high reversible capacity of 392.7 mAh g−1 (volumetric capacity: 1531.5 mAh cm−3) with 93.5% utilization ratio of active materials at 0.1 A g−1 and a long-stable lifespan with 500 cycles at 1.0 A g−1 in Li-Te batteries. Besides, in-situ TEM and ex-situ SEM observations demonstrate a small volume expansion and strong structural robustness of porous Te during cycling, stemming from its inward expansion mechanism and 3D stable interconnected porous structure. This work demonstrates a simple and universal strategy to design sponge-like porous materials for energy storage and catalysis, etc.