Chemically Chargeable Photo Battery

Abstract

Here we show a surrogate strategy for power production, wherein light is used to actuate a discharge chemistry in the cathode of an aqueous rechargeable battery (ARB). The proposed photo battery consists of a titanium nitride photoanode, promising cathode material iron(III) hexacyanoferrate(II) as the battery active species and Na2S2O8 as the chemical charging agent. The photo battery delivered negligible capacity in the dark and the capacity shot up to 77.8 mAh/g when artificially shined light, confirming that the battery chemistry is light driven. In the ambient light, the device retained 72% of its artificial light discharge capacity with a stable cycling for more than 100 cycles. Further, an unprecedented means for charging the battery rapidly is presented using Na2S2O8 and it revitalized the battery in 30 s without any external bias. This methodology of expending a photoanode extends to a battery that is free from dissolution of active materials, irreversible structural changes, spontaneous deinsertion reactions, and safety concerns commonly encountered in the state of the art anode materials in ARBs. Apart from bringing out a sustainable way for power production, this device opens up avenues for charging the battery in the likely events of electrical input unavailability, while solving the critcial issues of longer charging time and higher charging voltage.