Effects of Salt Additives to the KOH Electrolyte Used in Ni/MH Batteries

Batteries

Suli Yan¹  Kwo-Hsiung Young¹  K.Y. Simon Ng¹ 

[1] Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA; E-Mails:

关键词: nickel metal hydride (Ni/MH) battery;    electrolyte additives;    corrosion;    MgNi based anodes;    alkaline halides;   

DOI  :  10.3390/batteries1010054

来源: mdpi

【 摘 要 】

KOH-based electrolytes with different salt additives were investigated to reduce their corrosive nature toward Mg/Ni metal hydride alloys used as negative electrodes in nickel metal hydride (Ni/MH) batteries. Alkaline metal halide salts and oxyacid salts were studied as additives to the traditional KOH electrolyte with concentrations varying from 0.005 M to 1.77 M. Effects of the cations and anions of the additives on charge/discharge performance are discussed. The reduction potential of alkaline cations and radii of halogen anions were correlated with initial capacity and degradation of the metal hydride alloy. A synergistic effect between KOH and some oxyacid salt additives was observed and greatly influenced by the nature of the salt additives. It was suggested that both the formation of a solid film over the metal hydride surface and the promotion of proton transfer in the additives containing electrolytes led to a decreased degradation of the electrodes and an increased discharge capacity. 12 salt additives, NaC₂H₃O₂, KC₂H₃O₂, K₂CO₃, Rb₂CO₃, Cs₂CO₃, K₃PO₄, Na₂WO₄, Rb₂SO₄, Cs₂SO₄, NaF, KF, and KBr, were found to increase the corrosion resistance of the MgNi-based metal hydride alloy.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.