With increasing demand for high performance energy storage devices, 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.1-4 In this talk, I will introduce the control in the physical structure and chemical composition of 2D nanomaterials for ultracapacitive energy storage devices under limited circumstances, where conditions are classified into thermodynamic (e.g. pressure, volume and temperature) and kinetic (e.g. high rate and frequency) variables.1-10 In addition, a fundamental foundation via in-situ spectroscopic techniques will be presented to understand charge storage phenomenon of new materials and devices occurring on a nanoscale under various circumstances.8-10 Reference [1] Ho Seok Park*, et al. Adv. Energy Mater., 2015, 1500959. [2] Ho Seok Park*, et al. ACS Nano., 2015, 9, 8569-8577. [3] Ho Seok Park*, et al. Adv. Funct. Mater., 2015, 25, 1053-1062. [4] Ho Seok Park*, et al. ACS Nano, 2011, 5, 5167-5174. [5] Ho Seok Park*, et al. Nano Lett., 2015, 15 (4), 2269-2277. [6] Ho Seok Park*, et al. Adv. Energy Mater., 2016, 6, 1501115. [7] Ho Seok Park*, et al. Adv. Energy Mater., 2018, 8, 1702930. [8] Ho Seok Park*, et al. ACS Energy Lett., 2018, 3, 724. [9] Ho Seok Park*, et al. Joule, 2019, 3, 1-13. [10] Ho Seok Park*, et al. Nature Materials, 2019, 18, 156-162.