High-temperature characteristics of advanced Ni-MH batteries using nickel electrodes containing CaF2

Capacity Degradation Mechanisms in Nickel/Metal Hydride Batteries

“…The irreversible capacity loss during long-term room temperature storage can be attributed to the dissolution of the surface CoOOH conducting network [115,116], corrosion/passivation of the negative electrode [23,[117][118][119], decomposition of the positive electrode [115], decomposition of the separator [116], and poisoning of the positive electrode from cations that originate from the negative electrode [68,80,115].…”

“…For instance, a high energy consumer cell, a general purpose cell, and a high-rate cell may have n/p ranges of 1.05-1.2, 1.4-1.6, and 1.8-2.2, respectively. Adequate distribution of the extra negative electrode capacity into the over-charge-reservoir (OCR) and the over-discharge-reservoir (ODR) to avoid cell-venting is especially critical, particularly near the end of service life [116]. Nearly all cases of venting are due to short-circuits in the OCR that arises from material oxidation and γ-NiOOH formation that overwhelm the ODR.…”

High-temperature electrochemical performance of Al-α-nickel hydroxides modified by metallic cobalt or Y(OH)3

“…The difference (oxygen over-potential) between the oxygen evolution potential (E oe ) and the oxidation Eo and Eoe are defined as oxidation potential and oxygen evolution potential, respectively. potential (E o ) is defined as (E oe − E o ), which is usually used as the indicator of charge efficiency and charge acceptance [23,32,37]. It is found that there is only one anodic (oxidation) and one cathodic (reduction) peak in the curves for the three samples at room temperature and at high temperature (60 • C).…”

“…Therefore, considerable efforts in the past years were made to improve the high-temperature electrochemical performance of spherical ␤-Ni(OH) 2 . Among all additives, cobalt hydroxides [14,15], calcium hydroxides [16], lanthanide oxides or hydroxides [17][18][19][20][21][22], and CaF 2 /Co(OH) 2 , Ca 3 (PO 4 ) 2 /Co(OH) 2 or Yb(OH) 3 /Co(OH) 2 composites [23][24][25] were usually added into spherical ␤-Ni(OH) 2 to improve the high-temperature electrochemical performance. Based on these achievements, the oxygen evolution of spherical ␤-Ni(OH) 2 by surface modification with metallic cobalt and cobalt hydroxides can be depressed and the charge-discharge reversibility was subsequently improved [15,25,26].…”

Morphology and Electrochemical Performance of Amorphous Nickel Hydroxide Added Anion

“…The obtained nickel electrodes were dried at 80 ˚C and then pressed at 8 MPa for 3 min to assure good electrical contact between the nickel foam and active material. A mixture of 6 mol L -1 KOH + 18 g L -1 LiOH was applied as the electrolyte [11][12] . Cyclic voltammetry (CV) was performed on Auto-lab electrochemistry workstation in a three-electrode system with an Hg/HgO as reference electrode and nickel foam sheet as counter electrode.…”