Regulation of the discharge reservoir of negative electrodes in Ni–MH batteries by using Ni(OH)x (x = 2.10) and γ-CoOOH

In this paper, a novel strategy to regulate the discharge reservoir of negative electrodes in Ni–MH batteries is introduced by using Ni(OH)x (x = 2.10) and γ-CoOOH. The electrochemical measurements of these batteries demonstrate that the use of Ni(OH)x (x = 2.10) and γ-CoOOH can not only successfully regulate the discharge reservoir of negative electrodes in Ni–MH batteries to an adequate quantity, but also effectively improve the electrochemical performance of the batteries. Compared with normal batteries, the in-house prepared batteries with a lower discharge reservoir exhibit an enhanced discharge capacity, improved high-rate discharge ability, higher discharge potential plateau and superior cycle stability. The effect of Ni(OH)x (x = 2.10) and γ-CoOOH on the electrochemical performance of nickel electrode is also investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results suggest that the new method is simple and effective for cost reduction of Ni–MH batteries with improved electrochemical performance.

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► The surplus capacity of the MH electrodes in Ni–MH batteries was reduced by using Ni(OH)x (x = 2.1) and γ-CoOOH.
► Ni(OH)x (x = 2.1) and γ-CoOOH can not only regulate the discharge reservoir of negative electrodes to an adequate quantity, but also effectively improve the electrochemical performance of the batteries.
► The batteries with a lower discharge reservoir exhibit enhanced discharge capacity, improved high-rate discharge ability and superior cycle stability.