Micron-sized Fe-Cu-Si ternary composite anodes for high energy Li-ion batteries

Abstract

Nano-engineering of silicon anodes has contributed to the demonstration of a promising potential for high energy lithium ion batteries, through addressing the degradation of battery performance derived from severe volume changes during cycling. However, the practical use of nano-engineered silicon anodes is still stuck because of remaining challenges, such as the low tap density, poor scalability and inferior electrical properties. Herein, we successfully developed a new Fe-Cu-Si ternary composite (FeCuSi) by scalable spray drying and facile heat treatment. As a result, FeCuSi exhibited remarkable initial Coulombic efficiency (91%) and specific capacity (1287 mA h g-1). In order to exactly characterize the electrical properties of FeCuSi and directly compare them with industrially developed benchmarking samples such as silicon monoxide (SiO) and a silicon-metal alloy (Si2Fe), both half-cell and full-cell tests were performed with high electrode density (1.6 g cc-1) and high areal capacity (3.4 mA h cm-2). Overall, FeCuSi outperformed the benchmarking samples in terms of discharge capacity and capacity retention in high mass loading for 300 cycles.