This study investigates the sorption of aqueous electrolytes in porous carbon using NMR spectroscopy. The research focuses on the adsorption of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in activated carbon YP-50F across a wide range of pH values. The study highlights the importance of considering the role of hydronium (H₃O⁺) and hydroxide (OH⁻) ions in ion adsorption and surface charge distribution. The study begins with pH measurements to quantify the adsorption of H₃O⁺ ions, revealing that the activated carbon YP-50F has a very basic point of zero charge (PZC), indicating strong basicity on the carbon surface. Solid-state NMR spectroscopy is used to study the uptake of LiTFSI in YP-50F across the full pH range. The NMR data analysis emphasizes the importance of including fast ion-exchange processes for accurate quantification of adsorbed ions. Under acidic conditions, more TFSI⁻ ions are adsorbed in the carbon pores than Li⁺ ions, with charge compensation also occurring via H₃O⁺ adsorption. Under neutral and basic conditions, when the carbon's surface charge is close to zero, Li⁺ and TFSI⁻ ions exhibit similar but lower affinities toward the carbon pores. The study provides a methodology to relate the local structure to the function and performance in a wide range of materials for energy applications. The study also explores the impact of pH on ion adsorption, showing that the chemical shifts of in-pore ions vary with pH. The results indicate that the carbon pores become more ionophilic as the electrolyte becomes more acidic, which has important implications for the charge storage mechanisms of aqueous electrochemical systems. The study further demonstrates that the capacitance of YP-50F carbon increases significantly when using acidic electrolytes. The findings contribute to a better understanding of the role of H₃O⁺ and OH⁻ ions in ion adsorption and surface charge distribution in porous carbon electrodes.This study investigates the sorption of aqueous electrolytes in porous carbon using NMR spectroscopy. The research focuses on the adsorption of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in activated carbon YP-50F across a wide range of pH values. The study highlights the importance of considering the role of hydronium (H₃O⁺) and hydroxide (OH⁻) ions in ion adsorption and surface charge distribution. The study begins with pH measurements to quantify the adsorption of H₃O⁺ ions, revealing that the activated carbon YP-50F has a very basic point of zero charge (PZC), indicating strong basicity on the carbon surface. Solid-state NMR spectroscopy is used to study the uptake of LiTFSI in YP-50F across the full pH range. The NMR data analysis emphasizes the importance of including fast ion-exchange processes for accurate quantification of adsorbed ions. Under acidic conditions, more TFSI⁻ ions are adsorbed in the carbon pores than Li⁺ ions, with charge compensation also occurring via H₃O⁺ adsorption. Under neutral and basic conditions, when the carbon's surface charge is close to zero, Li⁺ and TFSI⁻ ions exhibit similar but lower affinities toward the carbon pores. The study provides a methodology to relate the local structure to the function and performance in a wide range of materials for energy applications. The study also explores the impact of pH on ion adsorption, showing that the chemical shifts of in-pore ions vary with pH. The results indicate that the carbon pores become more ionophilic as the electrolyte becomes more acidic, which has important implications for the charge storage mechanisms of aqueous electrochemical systems. The study further demonstrates that the capacitance of YP-50F carbon increases significantly when using acidic electrolytes. The findings contribute to a better understanding of the role of H₃O⁺ and OH⁻ ions in ion adsorption and surface charge distribution in porous carbon electrodes.