Investigating the charge-discharge behaviour of Ni(OH)2 nanowalls

Abstract

Ni(OH)2 nanowalls samples, formed by a network of < 20 nm thick nanosheets, were grown onto conductive substrates by low-cost chemical bath deposition (CBD), and a fully charged or discharged state in nanowalls was achieved by voltammetric experiments in 1 M KOH. Scanning electron microscopy (SEM), cyclic voltammetry (CV), Raman spectroscopy and Elastic Recoil Detection Analysis (ERDA) indicated multiple phases in both charged (γ-NiOOH, β-NiOOH) and discharged (α-Ni(OH)2, β-Ni(OH)2) state. A careful estimation of the H content in charged and discharged nanowalls corroborates the specific capacity measurement got by conventional electrochemical cyclic voltammetry (CV). A high proton diffusion coefficient of (2.99 ± 0.05) × 10−11 cm2 s−1 was estimated and attributed to the unique design of nanowalls, resulting in a high specific capacity.