Electrochemical Behavior of Rechargeable Al-Ni Battery Systems in Concentrated [EMIm]Cl-AlCl3 Electrolyte

In this work, the electrochemical behavior of the Al-Ni battery system in electrolyte composed of aluminum chloride (AICl(3)) and 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) with a molar ratio of 1.3 is investigated. The results reveal that the reversible capacity, which is based on the de/alloying process of Al on a Ni cathode, can be triggered only once the Ni electrode has been chlorinated. The value of reversible capacity is related to the chlorination degree of the nickel electrode. However, because the produced nickel chloride is soluble in the [EMIm]Cl-based electrolyte, the dissolved Ni2+ can migrate to the Al anode side and spontaneously react with the Al electrode, causing the battery to fail drastically. To safeguard the Al anode, an interlayer composed of AI powder is inserted between the separators to react with the dissolved Ni ions. The upgraded Al-Ni battery system can provide significantly improved performance, with cycling stability increasing from 84 to over 580 cycles in an 8 min controlled galvanostatic charge procedure.

Automated summary

The electrochemical behavior of the Al-Ni battery system in an electrolyte composed of aluminum chloride and 1-ethyl-3-methylimidazolium chloride was investigated. It was found that the de/alloying process of Al on a Ni cathode can be triggered once the Ni electrode has been chlorinated. However, the dissolved nickel chloride can react with the Al electrode, causing battery failure. An interlayer composed of AI powder was inserted to protect the Al anode and significantly improve battery performance.