A review of binder-free electrodes for advanced supercapacitors

Supercapacitors are high-performance electrochemical energy storage devices with high power density, long cycle life, and rapid charge and discharge capabilities. However, in the conventional electrode fabrication process, the addition of binders without conductivity and electrochemical activity reduces the mass of active materials and increases resistance in the electrode, which compromises its electrochemical performance. Therefore, the binder-free electrode is an effective method to enhance the electrochemical performance and energy density of electrodes. The different fabrication technologies for binder-free electrodes have been explored in detail, especially focusing on surface growth on current collectors, self-assembly techniques, and the new technological methods. The design of electrochemically active materials, including carbon, metal compounds, and conductive polymers have been emphasized, along with the optimization of processes and the enhancement of performance, interface engineering and improvements in electrode functionality, the utilization of multifunctional performance materials, and the design and optimization strategies grounded in theoretical simulations. Depending on the actual situation, binder-free electrodes can increase energy density and specific capacitance 10% to 30% approximately. Finally, the advantages of binder-free electrode technology in supercapacitors and other energy storage fields are introduced, further exploring future research directions and the potential breakthroughs and challenges that binder-free electrode technology may bring.