This study reports a novel electrochemical exfoliation method for producing high-quality graphene sheets from graphite in aqueous solutions of inorganic salts, such as ammonium sulfate ((NH4)2SO4), sodium sulfate (Na2SO4), and potassium sulfate (K2SO4). The method yields graphene with a high yield (>85%), large lateral size (up to 44 μm), low oxidation degree (C/O ratio of 17.2), and excellent hole mobility (310 cm² V⁻¹ s⁻¹). The graphene sheets are highly conductive, with a sheet resistance of 1.96 kΩ sq⁻¹, and can be easily dispersed in N,N'-dimethylformamide (DMF) to create concentrated graphene ink. This ink can be applied to A4-sized paper using a paintbrush to form highly conductive and mechanically stable graphene films with a sheet resistance of ~11 Ω sq⁻¹. All-solid-state flexible supercapacitors fabricated using these graphene films exhibit a high area capacitance of 11.3 mF cm⁻² and excellent rate capability (up to 5000 mV s⁻¹). The electrochemical exfoliation method shows promise for industrial-scale production of high-quality graphene for various advanced applications.This study reports a novel electrochemical exfoliation method for producing high-quality graphene sheets from graphite in aqueous solutions of inorganic salts, such as ammonium sulfate ((NH4)2SO4), sodium sulfate (Na2SO4), and potassium sulfate (K2SO4). The method yields graphene with a high yield (>85%), large lateral size (up to 44 μm), low oxidation degree (C/O ratio of 17.2), and excellent hole mobility (310 cm² V⁻¹ s⁻¹). The graphene sheets are highly conductive, with a sheet resistance of 1.96 kΩ sq⁻¹, and can be easily dispersed in N,N'-dimethylformamide (DMF) to create concentrated graphene ink. This ink can be applied to A4-sized paper using a paintbrush to form highly conductive and mechanically stable graphene films with a sheet resistance of ~11 Ω sq⁻¹. All-solid-state flexible supercapacitors fabricated using these graphene films exhibit a high area capacitance of 11.3 mF cm⁻² and excellent rate capability (up to 5000 mV s⁻¹). The electrochemical exfoliation method shows promise for industrial-scale production of high-quality graphene for various advanced applications.