Research On Preparation And Performance Of Non-aqueous System Liquid Flow Energy Storage Battery

Chemical energy storage is generally used in small and flexible scenarios.A redox flow battery that can be widely used is favored.However,the electrolytes in practical applications are mostly aqueous flow energy storage batteries,which have the problem of a smaller electrochemical window.The development of non-aqueous flow batteries with a larger electrochemical window has become a research hotspot.Most non-aqueous ionic liquids are expensive and pollute the environment,Choline Chloride and Ethylene Glycol(ChCl-EG)Deep Eutectic Solvent(DES)is a non-aqueous system with wide electrochemical window,green environmental protection,and low price,and has many applications in the electrochemical field.It is possible to develop Redox Flow Battery(RFB)based on ChCl-EG DES.Based on ChCl-EG DES,this paper studied the related properties of ChCl-EG DES containing active substances and assembled Zn-Ce RFB,Ti-Ce RFB and Mg-Ce RFB according to the redox properties of active substances.The performance of the battery was studied through charge-discharge test.The specific research contents are as follows:(1)The physicochemical properties of ChCl-EG DES containing CeCl3 were studied.The complexation mode of CeCl3 in ChCl-EG was determined mainly through the combination of infrared spectroscopy and Raman spectroscopy.And through the test of the viscosity and conductivity of the ChCl-EG DES containing CeCl3,it was found that with the increase of temperature in the experiment,the viscosity of the DES decreased,and its conductivity increased.(2)The static H-type Zn-Ce RFB was assembled based on ChCl-EG DES,and the diffusion control of Ce3+in ChCl-EG was obtained in the cyclic voltammetry test of the active substance Ce3+in the cathode electrolyte.The effects of Ce3+concentration,temperature and different charge-discharge current densities on battery performance were studied,and the best charge-discharge conditions were obtained.The battery attenuation test verifies that the Zn-Ce RFB has good stability.(3)Due to the deposition reaction of Zn2+ in Zn-Ce RFB,the anode electrolyte has become an important factor limiting the service life of the battery.Therefore,the development of new anode electrolyte can effectively solve this problem.Static H-type Ti-Ce RFB was assembled based on ChCl-EG DES.Ti4+ is quasi-reversible in ChCl-EG by cyclic voltammetry.Infrared spectroscopy and Raman spectroscopy tests found that TiCl4 has three complexing methods in ChCl-EG,and the good stability of Ti-Ce RFB was verified in the battery attenuation test.(4)Mg2+is widely used in batteries,but less used in RFB.In this paper,a static Htype Mg-Ce RFB is assembled based on ChCl-EG DES to study whether Mg2+can be used in RFB.Cyclic voltammetry showed that the reaction of Mg2+in ChCl-EG was controlled by diffusion.The structural characterization experiment,it was found that MgCl2 had two complexing modes in ChCl-EG.The 40-cycle charge-discharge tests of Mg-Ce RFB showed that the battery had good performance,and Mg2+could be applied in RFB.