| Aluminum is a very attractive anode material for energy storage and conversion. Aluminum has promising development prospects because of its high electrochemical equivalent,negative electrode potential,environmentally friendly and low price. However,in air or aqueous solution aluminum is prone to passivation,and in strongly alkaline solution it corrodes severely with the production of large amount of hydrogen gases.This wasteful self-corrosion results in unacceptably high-energy loss during standby and the safe problem for the use of batteries.A successful electrode system should keep aluminum electrochemically active whilst reducing its corrosion rate to a low level.This paper mainly investigates the effects of surface treatment and stannate as an electrolyte additive on the corrosion and electrochemical performances of pure aluminum in alkaline methanol-water solutions.The first chapter reviewed the history of the usage of aluminum in electrochemical batteries as well as the development situation of various kinds of aluminum batteries.Then,the author briefly introduced the research development on the corrosion electrochemistry of pure aluminum and aluminum alloy,including corrosion methanism and inhitors,etc.In the second chapter,the general research ideas and experimental details of this dissertation were described.In the third chapter,the effects of surface treatment with stannate on the corrosion and electrochemical behaviors of pure aluminum in alkaline methanol-water solutions have been investigated.In our experimental range the aluminum electrode treated in the solution with 0.1 mol·L-1 NaOH,0.02 mol·L-1 Na2SnO3·4H2O,0.015 mol·L-1 CH3COONa and 0.02 mol·L-1 Na4P2O7·10H2O for 30 min showed relatively low corrosion rate and better discharge performance.In the 4.0 mol·L-1 KOH methanol-water mixed solutions with 30%water,the treated aluminum electrode presented much low corrosion rate(1.12 mA·cm-2),compared with the untreated aluminum electrode(5.01 mA·cm-2);the discharge time of the treated aluminum electrode at the current density of 20 mA·cm-2 reached 70 min,while the discharge duration of the untreated aluminum electrode was only 15 s.Based on these,the electrochemical performances of the surface-modified aluminum anode in the stannate-containing 4.0 mol·L-1 KOH solutions with 30%water were further explored. The addition of Na2SnO3 in the electrolytes slightly inhibited the corrosion of the modified aluminum electrodes,resulting from the further deposition of metallic tin in the aluminum surfaces.The existence of elemental tin might facilitate the formation of the porous discharge product film on the discharged aluminum surface,notably enhancing the discharge performance of the modified aluminum anode in the stannate-containing electrolyte.In the 4.0 mol·L-1 KOH methanol-water solution containing 30%water and 0.0015 mol·L-1 Na2SnO3,the discharge time of the treated aluminum electrode at the current density of 50 mA·cm-2 reached 25 h,maintaining the discharge voltage below -1400 mV.In the fourth chapter,the effects of the heat treatment at various temperatures on the electrochemical behaviors of the surface-modified aluminum electrode in the alkaline solutions were investigated.In the 4.0 mol·L-1 KOH methanol-water solution containing 30%water and 0.005 mol·L-1 Na2SnO3,the surface-modified aluminum electrode heat-treated at 300℃presented much longer discharge time(50 h) than the corresponding electrode without heat treatment at the current density of 50 mA·cm-2, although its corrosion current density(1.20 mA·cm-2) was slightly larger than that of the corresponding electrode without heat treatment.The obviously enhanced discharge performance of the surface-modified aluminum electrode heat-treated at 300℃might result from the change of its surface structure due to the heat treatment.
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