With increasing demand for high performance energy storage systems, the feasibility of reliable and functional energy storage devices that well operates under extreme conditions is of prime importance for expanding applicative fields as well as for understanding materials’ intrinsic and extrinsic properties and device physics. Our group has been investigating ultracapacitive energy storage materials and devices operating under limited circumstances, where conditions are classified into thermodynamic (e.g. pressure, volume and temperature) and kinetic (e.g. high rate and frequency) variables. In this talk, I will introduce high temperature operating, flexible supercapacitors based on graphene electrodes and polymer or gel electrolytes that can efficiently deliver electrical energy under electrochemical, mechanical and thermal stresses.^[1-4] In order to achieve high performance supercapacitor devices under thermal, mechanical and electrochemical stresses, the micro- and macroscopic structures and chemical compositions of graphenes are delicately controlled by chemical modification. For the case of electrolyte materials, both of electrochemical properties and mechanical integrity should be satisfied for high temperature device applications. A new generation of flexible supercapacitors, with the long-term durability and outstanding electrochemical properties, were realized, showing a high position of the Ragone plot, even under severe conditions.

References

[1] B. G. Choi, J. Hong, W. H. Hong, P. T. Hammond, ACS Nano, 5, 7205-7213 (2011).

[2] B. C. Kim, J. Y. Hong, G. G. Wallace, H. S. Park, Adv. Energy Mater, 5, 1500959 (2015).

[3] S. K. Kim, H. J. Kim, J. C. Lee, P. V. Braun, H. S. Park, ACS Nano, 9, 8569-8577 (2015).

[4] J. Y. Hong, B. M. Bak, J. J. Wie, J. Kong, H. S. Park, Adv. Funct. Mater., 25, 1053-1062 (2015).