A Reversible Hydrogen Ion Battery

Abstract

We demonstrate the proof of concept of an air chargeable and reversible H+-ion battery by exploiting the catalytic nature of Pt@C electrocatalyst in ionizing H2 and O2 molecules and the proton coupled and reversible redox energy transformation between quinone (Q) and hydroquinone (QH2) molecules. The unique feature of this battery is such that it delivers output power during discharge and air charge process making it a reversible H+-ion battery. Such a battery could be cycled for 200 cycles with decent capacity retention with concomitant power production during the discharge and air charge chemistries. Electrochemistry, Galvano-static intermittent titration technique (GITT), rotating ring disk electrode (RRDE) measurements, UV-Vis spectroelectrochemistry, FTIR and Raman spectroscopic analysis reveal a transition from Q to QH2 during the discharge chemistry. However during the air charge chemistry, formation of quinhydrone, the charge transfer complex between quinone and hydroquinone was dominantly observed. The catalytic nature of Pt@C towards H2 oxidation could be further exploited to design an electrically rechargeable H+-ion battery which could be cycled for over 300 cycles with decent capacity retention. Investigation by various physico chemical techniques revealed a reversible redox energy transition between Q and QH2 (possibly via quinhydrone) during discharge and electrical charge processes. In an era of energy crisis, it is indeed inevitable to store and use every bit of energy and we believe our strategy is a right step ahead in this direction.