In this study, we synthesize two layered and amorphous structures of germanium phosphide (GeP5) and compare their electrochemical performances to better understand the role of layered, crystalline structures and their ability to control large volume expansions. We compare the results obtained with those of previous, conventional viewpoints addressing the effectiveness of amorphous phases in traditional anodes (Si, Ge, and Sn) to hinder electrode pulverization. By means of both comprehensive experimental characterizations and density functional theory calculations, we demonstrate that layered, crystalline GeP5 in a hybrid structure with multiwalled carbon nanotubes exhibits exceptionally good transport of electrons and electrolyte ions and tolerance to extensive volume changes and provides abundant reaction sites relative to an amorphous structure, resulting in a superior solid-electrolyte interphase layer and unprecedented initial Coulombic efficiencies in both Li-ion and Na-ion batteries. Moreover, the hybrid delivers excellent rate-capability (symmetric and asymmetric) performance and remarkable reversible discharge capacities, even at high current rates, realizing ultradurable cycles in both applications. The findings of this investigation are expected to offer insights into the design and application of layered materials in various devices.
Bibliographical noteFunding Information:
This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP), the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (no. 20172420108590), and the National Research Foundation of Korea Grant funded by the Korean Government (MSIP) (NRF-2011-0030542).
Copyright © 2019 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)