Preparation Of Aqueous Zinc Ion Battery Electrolyte And Application In Zinc Quinone Battery

Aqueous zinc ion batteries（AZIBs）have attracted much attention in the field of electrochemical energy storage due to the advantages of low cost,non-toxicity and environmental friendliness.However,the commercial application of AZIBs is hindered by the low coulomb efficiency,the readily produced by-product of zinc anode and the uncontrolled growth of zinc dendrite.In addition,the choice of cathode materials is also a difficult problem for AZIBs.Among the AZIBs cathode materials,organic quinone electrodes are promising cathode materials with good research prospects due to the advantages of low toxicity,sustainable resources and stable structure during charge and discharge.Adding additives to electrolyte has been widely used as an effective strategy in battery field,which can stabilize the interface between electrode and electrolyte,inhibit dendrite growth and improve the adaptability to extreme environment.Therefore,the study of electrolyte additive and organic quinone electrode is of great significance to the development of AZIBs.This thesis conducted a series of studies,focusing on electrolyte modification,solving the problem of zinc dendrites,constructing a high-capacity,and long-life aqueous zinc quinone battery.The main research contents are as follows:（1）In order to solve the problem of zinc anode dendrite and their by-products,trimethyl phosphate（TMP）was added into the aqueous zinc ion battery electrolyte,and the amount of TMP was optimized and applied to zinc quinone battery.The results show that the electrolyte with 30 vol%TMP can effectively inhibit the dendrite growth and side reaction of zinc anode.Zn//PT battery assembled with metal zinc（Zn）as anode,5,7,12,14-pentaphenetracone（PT）as cathode and 30 vol%TMP as electrolyte show a reversible discharge capacity of 91.5 m Ah g^-1 at a current density of 2 A g^-1 after 9600cycles,corresponding to a capacity retention of 84.2%.This battery has a wide temperature adaptability and can work in the temperature range of-20～65℃.It is confirmed that the active center of the reactive PT cathode is a carbon-based functional group,which undergo a three-electron reaction.（2）In order to further improve the conductivity and dynamics of electrolyte,anions（CF₃SO₃^-and TFSI^-）and cations（Li⁺,Na⁺and K⁺）were added into the aqueous based electrolyte to investigate the effects on the electrolyte performance.The results show that the Zn//Zn symmetric battery using the[CF₃SO₃^-]anion based electrolyte has higher zinc ion plating/stripping stability than that with the[TFSI^-]anion based electrolyte.Compared with the Li⁺and Na⁺cation based electrolyte,K⁺cation based electrolyte has the highest plating/stripping stability,the lowest polarization voltage and the highest ionic conductivity(37.2 m S cm^-1).In the 0.5M K⁺-0.3TMP electrolyte,the Zn//Zn symmetric battery exhibits good cyclability in 800 h with a polarized voltage of 47 m V.PT cathode with the optimal electrolyte shows improved cycle life and capacity.At the current density of 10 A g^-1,the discharge capacity of the Zn//PT battery is 73 m Ah g^-1 and the capacity retention rate is about 65%after 11000 cycles.