Performance of sodium-ion supercapattery using LaMnO3 and rGO in non-aqueous electrolyte

Abstract

Nanostructured perovskite oxide LaMnO₃ was successfully synthesized by a one-step surfactant-assisted hydrothermal method. The as-prepared perovskite was characterized by various material characterization techniques. The characterizations revealed that the LaMnO₃ had Mn³⁺ and Mn⁴⁺ with oxygen and La³⁺ vacancies. Electrochemical measurements including cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) cycling, and electrochemical impedance spectroscopy (EIS) were carried out in aqueous as well as non-aqueous electrolytes. An aqueous supercapattery fabricated in the form of a CR2032 coin cell delivered a specific energy of 154 W h kg⁻¹ at a specific power of 324 W kg⁻¹ in 1 M KOH. Interestingly, sodium-ion and lithium-ion supercapatteries were fabricated for the first time in non-aqueous electrolyte that exhibited high specific energies of 236 W h kg⁻¹ and 123 W h kg⁻¹ at specific powers of 3630 W kg⁻¹ and 1430 W kg⁻¹, respectively, and excellent charge retention of over 95% even at the 10 000th charge–discharge cycle. The exhibited high specific energy was attributed to electrochemical insertion of Na⁺/Li⁺ ions into cation vacancies in the LaMnO₃. A prototype pouch cell with non-aqueous electrolyte was demonstrated to power a red colour LED and hollow-box-type LED bulbs.