Theoretical energy density above 1000 Wh kg −1 /800 Wh L −1 and electromotive force over 1.5 V are taken as the screening criteria to reveal significant battery systems for the next-generation energy storage. Practical energy densities of the cells are estimated using a solid-state pouch cell with electrolyte of PEO/LiTFSI.
As a result, commercially available supercapacitors typically exhibit energy densities ranging from 1 to 10 Wh/kg, significantly lower than lithium-ion batteries (100–265 Wh/kg) , . The energy density (Wh/kg) and power density (kW/kg) of supercapacitors are compared with lithium-ion batteries and lead-acid batteries in Fig. 5.
The race to develop novel methods for enhancing their electrochemical characteristics is still going strong, where the goal of improving their energy density to match that of batteries by increasing their specific capacitance and raising their working voltage while maintaining high power capability and cutting the cost of production.
Electrochemical supercapacitors: scientific fundamentals and technological applications. Abstract Supercapacitors (SCs) are potentially trustworthy energy storage devices, therefore getting huge attention from researchers. However, due to limited capacitance and low energy density, the...
Energy density of batteries experienced significant boost thanks to the successful commercialization of lithium-ion batteries (LIB) in the 1990s. Energy densities of LIB increase at a rate less than 3% in the last 25 years . Practically, the energy densities of 240–250 Wh kg −1 and 550-600 Wh L −1 have been achieved for power batteries.
As a novel energy storage device, supercapacitors with characteristics of large capacitance, high power density and long cycle life can meet the high requirements of energy storage units, having applied in portable instruments, data memory storage systems and electromobile, etc.