Among a wide variety of functional materials for use In energy storage systems, cellulose can be suggested as a promising candidate doe to its natural abundance, recyclability, and low cost Regarding numerous application fields of cellulose, cellulose-medlated activated carbons have been extensively Investigated as an alternative electrode active material for energy storage systems Including electric double-layer capacitors (EDLCs). A primary requirement of the activated carbons b the acquisition of well-defined meso-, micro-porous structure with high spedile surface area. To achieve this goal, we demonstrate a new class of coffee-mediated flavor activation as a new eco-friendly strategy to address the aforementioned Issue of chemical activation In the cellulose carbonization. Coffee b known to contain potassium Ion (K+) as a core element Espresso b selected as an eco-friendly chemical activation agent for cellulose carbonization. A piece of Kim wipes was soaked Into the espresso solution and then subjected to heat treatment leading to the preparation of (espresso-assisted) carbonized Klmwtpes (referred to as "EK-AC"). As a control sample, simply carbonized Klmwtpes without the aid of espresso (denoted as "K-AC") was synthesized. Structural uniqueness of the EK-AC was Investigated, with a particular focos on K+Induced micropore formation. Spurred by the structural superiority of EK-ACs as an exceptional activated carbon material, we developed all-paper flexible supercapacitors (SCs) that were composed of EK-ACs/CNT electrodes, Kim wipes separator, and PVA/KOH solid electrolyte.