Systematic analysis of double electric layer capacitors in modern energy storage

The article discusses the operational principle and structure of double-layer capacitors, which rapidly convert and store electrical energy through electrostatic interactions between charges. Based on Helmholtz's interface double electric layer theory, these capacitors create two ion layers on each electrode when charged, with the Helmholtz layer separating them, storing energy in an electric field. Electrodes with high specific surface areas facilitate significant capacitance by allowing more ions to accumulate. The energy storage mechanism is reversible, exceling in enduring countless charge and discharge cycles and it does not decay obviously. Performance evaluation involves assessing energy and power densities, which are crucial for applications like extending driving ranges in electric vehicles or powering portable devices. Electrolyte properties significantly impact operating voltage and stability, with wider electrochemical stability windows increasing energy density. Optimizing electrode surface area, pore structure, and temperature range maintains optimal performance. The introduction of pseudo capacitance effects through additives can achieve higher energy densities compared to conventional double-layer capacitors. In summary, supercapacitors offer fast charging and discharging capabilities, making them ideal for scenarios requiring instantaneous high-power output. By improving electrolyte and electrode characteristics, their performance can be enhanced, broadening their applicability in various industries.