α – MnO2 coated anion intercalated carbon nanowires: A high rate capability electrode material for supercapacitors

Abstract

Nanowires of α-MnO2 coated phosphate anion intercalated carbon materials are synthesized using a simple hydrothermal method and characterized for its structure, composition, morphology, surface area, and electrochemical properties. The prepared material exhibits a specific capacitance of 362 F g−1 (areal capacitance of 212 mF cm−2) at a current density of 1 A g−1 in 1 M Na2SO4 electrolyte. The intercalated phosphate anions create more active sites for the enhanced reactivity and inhibit the dissolution of MnO2 during charge-discharge. The electrode offers a long cycle life with 80% capacitance retention for more than 2000 cycles. The core-shell structured nanowire morphology provides the best rate capability, high stability, and low charge transfer resistance which favour good supercapacitor performance.