| Aluminum air battery has an extraordinary theoretical energy density.As one of the key components of aluminum air battery,the storage life of aluminum anode is irreversibly limited by hydrogen evolution corrosion,which greatly reduces the utilization rate of aluminum anode.Current corrosion suppression solutions usually make great sacrifices in terms of energy density and power density.In this paper,a series of high-potential elements with high hydrogen resolution（Sn,Ga,etc.）and rare earth elements La and Ce are added in the way of alloying to activate the aluminum alloy and reduce the self-corrosion reaction of the aluminum alloy by optimizing the composition of the aluminum alloy.In addition,aluminum anode has very high activity in strong alkaline electrolyte,but it is inevitable that aluminum anode will suffer serious hydrogen evolution corrosion.Adding corrosion inhibitor to the electrolyte is a low operation difficulty and low-cost method.It can inhibit the active sites of hydrogen evolution on the surface of aluminum anode by adjusting the aluminum/liquid interface,thus reducing the self-corrosion reaction of aluminum anode.In this paper,the electrochemical performance and corrosion resistance of aluminum alloy anode were studied by hydrogen evolution test,open circuit potential test,potentiodynamic polarization curve test,electrochemical impedance spectroscopy,scanning electron microscope and constant current discharge test of aluminum air battery.Then,on the basis of self-made aluminum alloy anode,the action mechanism of electrolyte corrosion inhibitor was explored.（1）An Al-0.07 Pb-0.5 Mg-0.1 Ga-0.1 Sn-x La-y Ce alloy anode was prepared using a well crucible resistance furnace.Through hydrogen evolution testing and potentiodynamic polarization curve testing,it is known that the addition of La and Ce significantly reduces the self-corrosion rate of aluminum alloy anodes.From the electrochemical impedance spectroscopy and corrosion morphology,it can be seen that La and Ce elements provide more grain boundaries by refining the grains,accelerating the dissolution of high-potential elements such as Sn and Ga into the electrolyte,and then being reduced and deposited onto the surface of the aluminum alloy to provide active sites to activate the aluminum alloy anode and cover the hydrogen evolution sites,thereby inhibiting the self-corrosion of the aluminum alloy.The constant current discharge test of aluminum air batteries shows that aluminum alloy anodes with 0.10%La and 0.15%Ce additions have the highest discharge voltage and the energy density at 60 m A·cm-2,with the energy densities of 1968.30（battery voltage is 1.14 V）and 2144.20 m Wh·g-1（battery voltage is 1.14 V）.（2）Aluminum anodes exhibit significant differences in performance in 4 mol·L-1KOH solutions without and with different corrosion inhibitors.According to hydrogen evolution testing and corrosion morphology observation,the addition of corrosion inhibitors successfully inhibited the self-corrosion of aluminum alloy anodes.In the electrolyte added with composite corrosion inhibitors,the self-corrosion rate is the smallest and the surface corrosion degree is the lightest.The test results of open circuit potential and potentiodynamic polarization curves show that the aluminum alloy anode has the most negative corrosion potential（-1.57 V）and the minimum corrosion current density(19.25 m A·cm-2)in the electrolyte added with composite corrosion inhibitors,which is consistent with the hydrogen evolution test results.From the constant current discharge test of aluminum air batteries,it can be seen that the aluminum air batteries with composite corrosion inhibitors have a high discharge voltage of 1.50 V(current density of50 m A·cm-2),at which time the energy density is 3311.26 m Wh·g-1,and the power density is 75 m W·cm-2.In addition,at a high current density of 100 m A·cm-2,the aluminum air batteries with composite corrosion inhibitors can still output a battery voltage of 1.04 V,with a power density of up to 104 m W·cm-2,and a slight decrease in energy density of2606.52 m Wh·g-1,which is caused by a significant decrease in battery voltage. |
PDF Full Text Request