In high-speed iron batteries, many materials can be used as battery negative electrodes, including zinc, aluminum, iron, cadmium and magnesium. According to the metallic properties of zinc, its equilibrium potential is relatively negative and its electrochemical equivalent is relatively high, so its specific energy and specific power are relatively high. In addition, zinc has good discharge performance, is cheap and has abundant sources. It is widely used in chemical feeds.
In alkaline solution, in addition to the formation of zincate, the final product of the zinc electrode reaction is mainly zinc oxide in the solid phase:
Zn + 2OH-→Zn(OH) 2 + 2e
Zn(OH)2 + 2OH-→Zn(OH)42-
Zn(OH)42-→ZnO + H2O + 2OH-
p >The total reaction is: Zn + 2OH- →ZnO + H2O + 2e
For zinc anodes, it has some advantages whenIt is used in high-speed iron batteries because zinc electrodes, as anode materials, perform better in alkaline solutions. Accumulation of mature theories and techniques. When studying Zn-MFeO4 batteries, many technologies can be used as reference in terms of corrosion inhibitors, conductive agents, separators, current collectors and manufacturing processes. The reaction of the iron electrode as the negative electrode of the battery in an alkaline solution is relatively complicated. Iron loses electrons to form stable +2-valent and +3-valent hydroxides, i.e.
Fe + nOH-. → Fe(OH) n2-n +2e
Fe(OH)n2-n →Fe(OH)2+ (n-2)OH- E°= -0.877V (vs. SHE)< /p>
Fe(OH)2 + OH- →Fe(OH)3+ e E°= -0.56 V (vs. SHE)
Then, 2Fe(OH)3 + Fe(OH)2 → Fe3O4 + 4HO, and Fe3O4 is formed by the interaction between +3-valent iron and +2-valent iron.
Wheniron and ferrate form a battery, the open circuit voltage of the battery is approximately 1.5V, which varies slightly depending on the type of ferrate. It can be seen from the discharge curve of the iron electrode that the negative iron electrode has two discharge platforms during discharge. The first discharge platform corresponds to the conversion of Fe to Fe(OH)2; )2 /Fe(OH)3, the voltage from the first discharge platform to the second discharge platform will decrease by about 0.3 V. In fact, the flow rate of the second platform is easily affected by many factors. For example, Fe(OH)3, the reaction product of the second discharge product and ferrate, will form Fe3O4 with Fe(OH)2, which affects the discharge of Fe(OH)2. The theoretical capacity of a single battery composed of iron negative electrode and potassium ferrate at the first discharge platform should be 285.3 mAh/g. ferric acidSalt is also trvery stable and almost insoluble in certain non-aqueous organic media such as acetonitrile, ethylene carbonate (EC), propylene carbonate (PC), ethylene glycol dimethyl ether (DEM) and tetrahydrofuran (THF ). This allows ferrate to be used as a cathode material in non-aqueous electrolyte batteries. Lithium batteries have the characteristics of high voltage and high specific energy and are widely used in fields such as medicine, military, navigation and electronics.