Generic synthesis of high-entropy phosphides for fast and stable Li-ion storage
Publication Name
Energy and Environmental Science
Abstract
Monophosphides and bi-metallic phosphides have attracted considerable interest for their high-capacity Li-storage capacity, but are currently plagued by the sluggish charge transfer kinetics and large volume changes that hinder their practical applications. Herein, we design a triple-disordered-cation phosphide of GaGeSiP3 that combines the benefits of the high capacity of Si, high reactivity of P, fast Li ion conduction of Ge, and the self-healing capability of liquid metallic Ga. The GaGeSiP3 multinary compound features high configurational entropy, with excellent electronic conductivity, rapid Li-ion diffusion, and better resistance to volume change compared to the parent phases of GaGe2P3, GaSi2P3, Ge, and Si. Crystallographic and spectrographic analyses, electrochemical characterization and theoretical simulations confirm that GaGeSiP3 undergoes a reversible lithium storage mechanism based on a combination of intercalation and conversion reactions. The GaGeSiP3 anode delivers a high specific capacity of 1667 mA h g−1 with an initial coulombic efficiency of 90.3% and a low average operating potential of 0.47 V. Moreover, we further create graphite-modified GaGeSiP3 that combines intercalation and conversion storage to deliver a high rate capacity of 949 mA h g−1 at 20.0 mA cm−2, and an exceptional cycling stability to retain a capacity of 1121 mA h g−1 after 2000 cycles at 6.0 mA cm−2. Inspired by this unique feature of high structural entropy, we further synthesized quaternary mixed-cation ZnGaGeSiP4, CuGaGeSiP4, and AlGaGeSiP4; quinary mixed-cation ZnCuGaGeSiP5, ZnAlGaGeSiP5, and CuAlGaGeSiP5; and hexanary mixed-cation ZnCuAlGaGeSiP6, where the crystalline size was reduced due to the enhanced structural entropy. This work opens up a new synthesis paradigm, which overcomes the thermodynamic immiscibility among different metals and non-metals, for creating an attractive family of high-entropy multinary mixed-cation phosphides as advanced energy storage materials.
Open Access Status
This publication is not available as open access
Funding Number
22178068
Funding Sponsor
College of Science, Sungkyunkwan University