Recent development in metal-organic frameworks and their derivatives for supercapacitors

Renewable energy (hydrogen energy, wind energy, etc.) has attracted great attention considering the large consumption of fossil fuels and the strategic goal of carbon neutralization and carbon peak. However, due to the intermittence of clean energy, efficient energy storage devices are urgently needed for providing continuous power. An electrochemical capacitor, also known as a supercapacitor (SC), is an electrochemical energy storage device connecting traditional capacitor and battery. It fills the gap between the high specific power of traditional capacitors and the high specific energy of the batteries. Compared with batteries, SC has higher power density, long cycle lifespan, and the capability of fast charging and discharging. Moreover, SC possesses much higher energy density than traditional capacitors. Figures in the chapter compare the different properties of SCs, capacitors, and batteries, highlighting the unique role of SCs. SCs own the advantages of ultrafast charging/discharging, high safety, long-term stability, and outstanding power performance, showing great promise as power sources for applications like start-up engines, electronic devices, high-speed trains, etc. Metal-organic frameworks (MOFs) and their derivatives have shown great application prospects for SCs because of their adjustable structure, large specific surface area, rich porosity, atomically precise crystal phase, and rich species (> 75,000).