Poly(3,4-ethylenedioxythiophene) coated lead negative plates for hybrid energy storage systems

Highlights: • PEDOT coating reduces H₂ evolution and enhances the charge acceptance. • PEDOT modified lead acid cell improves C rate performances, cycle life. • PEDOT modified lead acid cell shows 107% increase HRPSoC cycling. • PEDOT shows specific capacitance of 105 F g⁻¹ at 2 A g⁻¹, stable over 20,000 cycles. -- Abstract: Herein, we report Poly(3,4-ethylenedioxythiophene) coating on to lead negative plates as a hybrid electrode material for lead-acid batteries and supercapacitors. Poly(3,4-ethylenedioxythiophene) coating on to negative plate addresses the issue of sulfation at negative plate in a lead-acid cell. Poly(3,4-ethylenedioxythiophene) coating on to the conventional negative plates is wind up by electropolymerization technique. 2 V/2.1 A h lead-acid cells assemble with Poly(3,4-ethylenedioxythiophene) coating negative electrodes show ∼25% increase in initial discharge capacity, excellent cycle performance at 5 h rate, lower impedance, reduce hydrogen evolution and boost charge acceptance in relation to the conventional lead-acid cell. The Poly(3,4-ethylenedioxythiophene) coating lead-acid cells show 20% improvement in C/5 rate and 107% in high rate partial state of charge cycling. The specific capacitance of Poly(3,4-ethylenedioxythiophene) in 4.5 M H₂SO₄ medium is about 105 F g⁻¹ with an excellent cycle life of over 20, 000 cycles at 2 A g⁻¹. The superior performance is due to fast kinetics of Poly(3,4-ethylenedioxythiophene) in sulfuric acid electrolyte.