Study On Anode Material For Aqueous Rechargeable Battery

In recent years,aqueous rechargeable batteries（ARBs）have attracted widespread attention owing to their advantages such as environmental friendliness,low cost and high security.However,with the limitation of the thermodynamic voltage window of water,there are few high-performing anode materials that can be used in ARBs.In order to solve the above problems,copper（Cu）metal and Ferroferric oxide（Fe₃O₄）were selected as negative electrode materials for ARBs in this thesis.Through optimizing the current collector-negative electrode interface and electrolyte control strategies,high specific capacity and stability negative electrodes for ARBs were developed,and its mechanism and electrochemical performance were deeply studied.The specific research contents and results are as follows:1.Cu metal is an attractive anode material of aqueous rechargeable batteries due to its high theoretical specific capacity(844 m Ah g^-1),good environmental compatibility and high earth abundance.However,the Cu metal anodes often suffer from some problems such as poor deposition/stripping reversibility and dendrite growth during the charge/discharge process,degrading the lifetime of aqueous Cu metal batteries.Herein,a lattice matching strategy was developed to select metal nickel（Ni）as current collector of Cu metal anode,and constructing a uniform current collector-negative electrode interface.The high lattice matching between Ni and Cu endows Cu anodes with high deposition/stripping reversibility,low nucleation overpotential as well as a uniform and dense electrodeposition morphology on Ni substrates.Based on the Ni substrate-supported Cu anodes,the full cells paired with lead dioxide（Pb O₂）cathode exhibit high operating voltage and stable cycle life.This work provides a route for the design of high-performance Cu metal anode in aqueous rechargeable batteries.2.Iron-based anode materials have attracted much attention owing to its high theoretical specific capacity,low electrode potential,low cost,environmentally friendly and dendrite free.However,iron-based anode materials inevitably subjected to hydrogen evolution,mainly due to their lower electrode potential and smaller hydrogen evolution overpotential.In this thesis,a strategy for regulating the structure of electrolyte was designed by adding a dimethyl sulfoxide（DMSO）organic solvent with a hydrogen bond receptor to potassium hydroxide electrolyte.The strong interaction between DMSO and water molecules inhibits the activity of water,thus hindering the water decomposition process.Therefore,a high coulombic efficiency and stable lifetime were obtained when Fe₃O₄ was used as the negative electrode.Compared with the traditional electrolyte,the Fe₃O₄∥Ni（OH）₂ batteries assembled with 0.5 DMSO/1 M KOH electrolyte exhibit higher discharge capacity and better cycle stability.Moreover,the self-discharge problems have also been further improved.This work provides new insights into the development of negative electrode materials for ARBs with low electrode potential,high specific capacity and high cycle stability.