UCLA researchers in the Schools of Engineering and Chemistry have developed a novel material for lithium-ion battery anodes. The composite exhibits unprecedented mass loading and energy storage capacity, expanding the applications and efficiency of lithium-ion batteries.
Lithium-ion batteries (LIBs) provide lightweight, energy-dense power sources for portable electronics, electric vehicles and military applications. The use of alloy-type anode materials in LIBs have attracted considerable interest as potential alternatives to the current graphite anodes due to their theoretical 11-fold higher energy density capacity versus graphite. The capacity of such alloy anodes in practice, however, have only had low area-normalized capacity, rarely exceeding capacity of current LIBs and have only approached theoretical capacity in research devices with relatively low mass loadings. In order to achieve the theoretical capacities of alloy LIBs, improved battery materials with lower internal resistance and high charge storage capacities in thicker electrodes with higher mass loadings are needed.
UCLA researchers have discovered an alloy-based composite material for LIBs anodes that exhibits close to theoretical area-normalized areal capacities in thicker electrodes. The composite is based on graphene and silicon nanoparticles that form a free-standing 3D framework structure. The anode has been successfully prototyped and tested to exhibit ultrahigh areal mass loading and ultrahigh areal capacity,considerably outperforming existing research and commercial LIBs.The material also exhibits much smaller overpotential and capacity degradation induced by mass loading at various C-rates. This innovation defines a critical step in exploring the high capacity alloy-type electrode materials for practical electrochemical energy storage devices.
The characteristics of the anode were tested in a galvanostatic electrochemical cell and tested with mass loadings up to 12 mg cm-2 at 500 mAg-1 and resulted in ultra-high aerial capacity up to 14.5 mAh cm–2 under current density of 0.2 mA cm–2 and stable areal capacity of 9.5 mAh cm–2 under current density of 2.4 mA cm–2.
lithium-ion batteries, anode, graphite, silicon oxide, nanoparticles, storage capacity, 3D-framework, mass loading, portable devices, electric vehicles, batteries