Ionic-Liquid-Based Design of a Recyclable NCM523 Electrode with Binder-Free, High Crystalline Characteristics

Recently, the demand for lithium-ion batteries (LIBs) has increased, with the continuous advancement in the use of high-performance devices. To satisfy this demand for LIBs, addressing their limitations, such as an unstable supply of material resources, high costs, environmental pollution, and resource nonrecyclability, is essential. Therefore, recycling of used active materials is crucial. Active material regeneration requires improvements in extracting active materials from the electrode. The binder is disadvantageous in terms of environmental impact and cost during recycling, as it generates fumes during heating and requires the use of toxic solvents during dissolution and removal. Binder-free electrode fabrication is thus an effective solution. However, conventional binder-free electrodes require special carbon auxiliaries with network structures, such as CNTs and carbon fibers. The use of the special carbons does not account for the CO2 generated during production or the cost of fabrication, which remain a challenge. Herein, we propose a novel binder-free battery electrode fabrication using ionic liquids in a single process. The ionic liquids effectively work as a reaction field to make binder-free electrodes consisting of NCM crystals and carbon in a three-dimensional composite. The electrodes exhibit high-power battery characteristics that are comparable to those of conventional commercial active materials and similar to 100% exfoliation efficiencies when heated. This study yields novel insights into the electrode design and its fabrication method to enable easy recycling. The results also suggest the influence of ionic liquids designing electrode structures. These findings may find extended applications, including various metal oxides for battery materials and several ionic liquids for solvents. Thus, our proposed designs should guide the development of binder-free electrodes yielding prospects for environmental protection, base metal recovery, and increased recycling revenue in a range of battery materials.