The development of high ion conducting membrane is in need of present time for efficient battery. The aim of this study is to develop a proton conducting polymer electrolyte using biopolymer sodium alginate (SA) with ammonium thiocyanate (NH₄SCN) salt using solution casting technique. Addition of graphene quantum dot (GQD) with the highest conducting polymer electrolyte resulted with the increase in ionic conductivity of the polymer electrolyte. The prepared composition of SA: NH₄SCN analyzed through XRD, FTIR, DSC, Ac impedance technique, LSV. SEM and TGA studies have been undertaken. The amorphous/crystalline natures of the obtained electrolytes were studied using the XRD technique. FTIR confirm the complex formation of salt and polymer. The glass transition temperature T_g has been obtained with the help of DSC. The highest proton conductivity of 8.72 × 10^–3 S cm⁻¹ has been obtained for the composition of 30 M.wt%SA: 70 M.wt%NH₄SCN. The ionic conductivity has been improved to 2.22 × 10^–2 S cm⁻¹ duo to the addition of 0.75 ml GQD with 30 M.wt%SA: 70 M.wt%NH₄SCN biopolymer electrolyte. Transference number analysis has been done using the Wagner’s polarization technique. Electrochemical stability value of 2.17 V (without GQD) and 2.83 V (with GQD) has been obtained using LSV. Proton conducting battery has been constructed using highest conducting biopolymer electrolyte and the open circuit voltage of 1.45 V (without GQD) and 1.48 V (with GQD) has been obtained. Construction of a single fuel cell has been made using highest proton conducting membrane providing an open circuit voltage 431 mV (without GQD) and 514 mV (with GQD).