Identifying The Factors Affecting The Working Life Of Zinc-Air Batteries

With the increasing dependence of modern society on energy,sustainable energy supply is essential for political stability and sustained economic development.Zinc-air batteries have received widespread attention due to their relatively high specific energy density(1218 Wh kg-1)and volumetric energy density(6136 Wh L-1).However,the current secondary zinc-air battery has not been commercialized.The main reason is that its working life is too short to meet the requirements of commercial applications.Although scholars have conducted many studies,there are still many problems in the commercialization of zinc-air batteries:On the one hand,a lot of work is carried out under laboratory conditions,using an electrolytic cell as a battery and injecting pure oxygen into it has masked some of the disadvantages of zinc-air batteries;on the other hand,many work discussions have only considered one single influencing factor,and there is no uniform battery performance evaluation standard and test environment,which also leads to differences between different jobs.In order to solve the above problems,we need to have a clearer understanding of the reasons for the decreased working life of zinc-air batteries and establish a unified battery performance evaluation benchmark.The specific work content is as follows:In the first part of this article,we studied the storage life of zinc-air batteries.First,a series of comparative experiments were carried out.By replacing various parts of the battery,it was confirmed that the key factor of battery failure was the carbonation of the electrolyte.In addition,the morphology and composition of the various components of the battery were also characterized.The SEM image showed that with the increase of storage days,the corrosion of the zinc anode gradually deepens,but the morphology of the air cathode did not change much.The electrolyte in batteries stored for different lengths of time was characterized by ICP(inductively coupled plasma spectrometer)and titration.It was found that the concentration of CO32-in the electrolyte reached 2.694 mol L-1 after the battery was stored for 20 days,which indicated that more than 80%of the OH-has been consumed in the electrolyte.In summary,in the storage process of zinc-air batteries,the carbonation of the electrolyte is the main reason for the decrease in battery capacity.In the second work of this article,we studied the cycle life of zinc-air batteries.Based on the three influencing factors of pore size,current density,and chargedischarge depth,a series of comparative experiments were designed,and the battery after the experiment was disassembled and characterized.The results showed that a small pore size helps to slow down the carbonation of the electrolyte,but a too small pore size may cause insufficient oxygen supply and cause the battery to stop working.A greater depth of discharge will cause severe deformation of the zinc anode,which will lead to battery failure.The larger current density will cause the carbon in the air electrode to dissolve and corrode,leading to the failure of the air electrode.