Effect of lightweight supports on specific discharge capacity of β-nickel hydroxide

Abstract

While the performance of β_bc (bc: badly crystalline)-nickel hydroxide is relatively unaffected by the use of different lightweight supports, the specific discharge capacity of crystalline β -Ni(OH)₂ doubles to approximately 355 mAh g^-1 Ni (theoretical, 456 mAh g^-1) when pasted to a fibre support compared with 170 mAh g^-1 Ni when pasted to a nickel foam. Consequently, the fibre is a superior support as it is unaffected by the quality of the active material and extracts a consistently high performance irrespective of the degree of crystallinity, moisture content, morphology and composition of the active material. Electrochemical impedance measurements indicate that a lower charge-transfer resistance at low states-of-charge is responsible for the superior performance of fibre supported β -Ni(OH)₂ electrodes.