Enhanced performance of carbon-free intermetallic zinc titanium alloy (Zn-ZnxTiy) anode for lithium-ion batteries

Abstract

A carbon-free intermetallic zinc titanium alloy (carbon-free Zn/Ti) anode, comprising active Zn nanoparticles finely dispersed in ZnxTiy (Zn0.6Ti0.4 and Zn3Ti) intermetallic buffer, is prepared via a thermal-treatment followed by a high-energy mechanical milling process for a lithium-ion battery (LIB) anode. As a counter-intuitive phenomenon, without the need of a carbon matrix, the carbon-free Zn/Ti alloy exhibits superior cyclic performance (similar to 1064 mAh cm(-3) of volumetric capacity after 350 cycles), a good rate capability (85% capacity retention at 3 A g(-1) compared to its capacity at 0.1 A g(-1)), and a high initial coulombic efficiency (88%). Although the use of hybrid TiC-C matrix as a control sample still affords highly stable cyclic performance and good rate capability, it exhibits a relatively lower capacity than a carbon-free alloy electrode. The enhanced performance of carbon-free Zn/Ti anodes for LIBs is owing to the presence of stable and cohesive ZnxTiy intermetallic phases that provide high conductivity and mechanical stability, thereby mitigating the large volume changes of Zn particles during the lithiation/delithiation processes. High-performance Zn-ZnxTiy can be seen as a new promising anode for the next-generation energy storage technology. (C) 2019 Published by Elsevier Ltd.