9. High Mass Loading Supercapacitors

The demand for energy storage devices is growing daily in stationaries and mobile applications. Commercial supercapacitors require a high (at least 30%) active electrode material mass of the whole device to fulfill particular applications’ energy and power density demands. Therefore, high mass loading supercapacitors have greatly interested in researching high-specific capacitance electrodes for the commercial application of high-energy storage devices. High mass loading in supercapacitor fabrication is challenging because of the sluggishness of electrical and ion migration kinetics. The commercial level supercapacitor requires high mass loading greater than 10 mg cm⁻² or film thickness of 150–200 µm. These are scaleable production parameters. On the other hand, the strategies adopted to lower the production cost reduce the supercapacitor’s performance. To overcome the adverse effects, researchers and scientists take many synthesis approaches to increase the pore distribution, the proper pore size for electrolytes, and improve the active surface area of electrode materials. Chemical vapor deposition, layer by layer deposition, aerogel, and hydrogel methods are used to create an advanced porous structure that provides an easy ion diffusion path. Apart from doping heteroatoms, intercalation in a layered structure and surface medication increase the active surface area, which controls the electrochemical performance of high mass loading supercapacitors. But the ion diffusion in electrode materials largely depends on the proper pore size, which quickly provides the path.