Cost-Effective Scalable Synthesis of Mesoporous Germanium Particles via a Redox-Transmetalation Reaction for High-Performance Energy Storage Devices

Abstract

Nanostructured germanium is a promising material for high-performance energy storage devices. However, synthesizing it in a cost-effective and simple manner on a large scale remains a significant challenge. Herein, we report a redox-transmetalation reaction-based route for the large-scale synthesis of mesoporous germanium particles from germanium oxide at temperatures of 420600 degrees C. We could confirm that a unique redox-transmetalation reaction occurs between Zn0 and Ge4+ at approximately 420 degrees C using temperature-dependent in situ X-ray absorption fine structure analysis. This reaction has several advantages, which include (i) the successful synthesis of germanium particles at a low temperature (similar to 450 degrees C), (ii) the accommodation of large volume changes, owing to the mesoporous structure of the germanium particles, and (iii) the ability to synthesize the particles in a cost-effective and scalable manner, as inexpensive metal oxides are used as the starting materials. The optimized mesoporous germanium anode exhibits a reversible capacity of similar to 1400 mA h g(1) after 300 cycles at a rate of 0.5 C (corresponding to the capacity retention of 99.5%), as well as stable cycling in a full cell containing a LiCoO2 cathode with a high energy density (charge capacity = 286.62 mA h cm(3)).