Gallium-Based Nanocomposites for High-Performance Lithium-Ion Batteries

With the development of various portable devices and electric vehicles, the importance of rechargeable batteries is increasing day by day. Among these rechargeable batteries, lithium-ion batteries are dominating the market due to their superior energy density and long cycle life. However, graphite, currently the most commonly used LIB anode material, has a relatively slow rate-capability and a limited theoretical capacity (LiC₆: 372 mAh g^–1). Li-alloy-based materials, such as Si, Sn, Ge, P, and Sb have high theoretical capacities and are therefore being researched as alternatives to graphite. However, these materials have a poor cycling behavior by the large volume changes during repeated cycling. Therefore, the search for high-capacity Li-alloy-based anode materials for LIBs that can overcome these shortcomings is highly required.<br/>Among these materials, gallium (Ga) has unique characteristics such as low melting temperature and fluidity. It can also alloy with Li and forms Li₂Ga (762 mAh g^–1) phase, ensuring a high theoretical capacity. Nevertheless, Ga-based anodes are easily agglomerated during lithiation/delithiation due to its low melting temperature (29.8 ^oC) and show a poor cycling behavior. In this study, various Ga-based nanocomposites were fabricated by a simple solid-state method and was applied as high-capacity anodes for LIBs. Among the various Ga-based nanocomposites, a Ga-based nanocomposite with Li-inactive metal carbide and amorphous C matrices was fabricated. The Ga-based nanocomposite with diverse matrices shows an enhanced reversibility with Li, high capacity retention of 525 mAh g^–1 after 200 cycles, and fast rate capability of 401 mAh g^–1 at 3C rate. Furthermore, the reaction mechanism between the Ga-based nanocomposite with Li was investigated thoroughly using various cutting-edge analytical tools.<br/><br/>Acknowledgements<br/>This work was supported by the National Research Foundation of Korea grant funded by the Korea Government (MSIP) (NRF-2021R1A2B5B01002570, NRF-2018R1A6A1A03025761). This research was supported by the MSIT (Ministry of Science and ICT), Korea, under the Grand Information Technology Research Center support program (IITP-2022-2020-0-01612) supervised by the IITP (Institute for Information & Communications Technology Planning & Evaluation).