Construction Of Gel-State Photo-Assisted Metal-Air Battery And Study Of Photoelectrochemical Mechanism

As the global population continues to grow and the economy rapidly develops,the demand for energy is increasing at an alarming pace.However,the current energy system heavily reliant on fossil fuels not only has limited supply but also causes severe pollution problems.Fortunately,solar energy presents as a sustainable,green,and clean alternative.Developing safe,cost-effective,and efficient energy conversion technology for storing solar energy is a current hot spot in social research.Metal-air batteries offer the most potential as an energy conversion storage device,thanks to their high specific energy,stability,environmental friendliness,low cost,and safety.To introduce solar energy into these batteries,a semiconductor photocatalytic material is used as the air electrode for the metal-air battery,thus improving the slow reaction kinetics and enabling the conversion of solar energy into electric energy.The main objective of this article is to examine the use of semiconductor photocatalytic materials in metal-air batteries,exploring their potential for expanding the use of renewable energy in the future.The main work of this article is as follows:1.The synthesis of Cu₂O and CuO photoelectrodes on conductive glass（FTO）was accomplished through electrodeposition and calcination.A photo-assisted Al-air battery was constructed with pure Al sheet as metal electrode,Cu₂O or CuO semiconductor materials as air electrodes,and calcium alginate hydrogel as electrolyte.Through the test method of offline gas chromatography hydrogen production,the self-corrosion degree of aluminum sheet in sodium hydroxide solution and calcium alginate gel was tested,and the results showed that calcium alginate hydrogel could effectively inhibit the corrosion of aluminum,thereby improving the discharge specific capacity of the battery.The electrochemical characterization of the constructed metal-air battery showed that the catalytic performance of CuO under illumination was better than that of Cu₂O and precious metal Pt.The discharge test was carried out under the condition of current density of 1 m A/cm²,and the test results showed that the discharge specific capacity of Al-air batteries with CuO film as air electrode when using calcium alginate hydrogel as electrolyte was 20 times that of sodium hydroxide solution as electrolyte.The performance will decrease during the discharge process,which was caused by the change of the valence state of copper,and the repeated discharge test results showed that the CuO after the valence change returned to the original valence state after calcination,and the photocatalytic performance remained basically unchanged.These findings open up a new possibility for the application of solar energy in Al-air batteries and also suggest a promising direction for inhibiting metal corrosion.2.TiO₂-CuO photoelectric materials were synthesized on conductive glass（FTO）using hydrothermal,electrodeposition,and calcination techniques.A new rechargeable photo-assisted Fe-air battery using TiO₂-CuO semiconductor material as air electrode,pure Fe sheet as metal electrode,and PVA gel containing ionic liquid（PVA/IL）as electrolyte was constructed.The photo-assisted Fe-air battery exhibited significantly higher short-circuit current,open-circuit voltage,and power density under illumination,as compared to those in the dark state.In addition,constant current charge and discharge tests carried out at a current density of 0.1 m A/cm² showed a decrease in charging voltage under illumination from 1.82 V to 1.52 V,and an increase in discharge voltage from 0.63 V to 1.2 V.These results indicated that utilizing solar energy can enhance the kinetics of the oxygen evolution reaction（OER）and oxygen reduction reaction（ORR）,reduced their reaction overpotential and facilitated the storage and utilization of solar energy.These findings lay the groundwork for the application of solar energy in photo-assisted Fe-air batteries.