Enhancement of discharge capacity and energy density by oxygen vacancies in nickel doped SrTiO3 as cathode for rechargeable alkaline zinc battery

Abstract

Rechargeable alkaline zinc batteries (RAZBs) are promising aqueous battery due to the advantages of Zn metal as the anode. Although the Zn anode is low cost, non-toxic, and intrinsic safety, the use of metal oxide cathode suffers from poor discharge capacity and energy density in RAZBs. The preparation of Nickel doped SrTiO3 (NiSTO) as cathode has successfully improved the performance of RAZBs up to 596 mAh cm−3 (2 mA cm−2) with energy density of 68 mWh cm−3. The discharge capacity is remarkability enhanced by 54% as compared to that of pristine STO as cathode. This proven that the formation of oxygen vacancies (Vo¨) after doped with nickel play an important role. The creation of Vo¨ enable more charge storage sites and also improve the electric conductivity which facilitates the diffusion of ions/electrons. Based on the charge-transfer resistance, the electrical conductivity of NiSTO has improved 79% from the 7.8 to 1.6 Ω. This outstanding performance of NiSTO as cathode has benefited RAZBs.