Anion storing,oxygen vacancy incorporated perovskite oxide composites for high-performance aqueous dual ion hybrid supercapacitors

Dual ion storage hybrid supercapacitors (HSCs) are considered as a promising device to overcome the limited energy density of existing supercapacitors while preserving high power and long cyclability.However,the development of high-capacity anion-storing materials,which can be paired with fast charging capacitive electrodes,lags behind cation-storing counterparts.Herein,we demonstrate the surface faradaic OH-storage mechanism of anion storing perovskite oxide composites and their application in high-performance dual ion HSCs.The oxygen vacancy and nanoparticle size of the reduced LaMnO3(rLaMnO3) were controlled,while r-LaMnO3was chemically coupled with ozonated carbon nanotubes(oCNTs) for the improved anion storing capacity and cycle performance.As taken by in-situ and exsitu spectroscopic and computational analyses,OH-ions are inserted into the oxygen vacancies coordinating with octahedral Mn with the increase in the oxidation state of Mn during the charging process or vice versa.Configuring OH-storing r-LaMnO3/oCNT composite with Na+storing MXene,the as-fabricated aqueous dual ion HSCs achieved the cycle performance of 73.3%over 10,000 cycles,delivering the maximum energy and power densities of 47.5 W h kg-1and 8 kW kg-1,respectively,far exceeding those of previously reported aqueous anion and dual ion storage cells.This research establishes a foundation for the unique anion storage mechanism of the defect engineered perovskite oxides and the advancement of dual ion hybrid energy storage devices with high energy and power densities.