In Situ Precipitation‐Induced Growth of Leaf‐like CuO Nanostructures on Cu–Ni Alloys for Binder‐Free Anodes in Li‐Ion Batteries

Abstract

CuC₂ O₄ ⋅x H₂ O was facilely prepared on a Cu-Ni alloy substrate by in situ precipitation-induced growth by using a mixture of sodium persulfate, hydrogen peroxide, and oxalic acid. Thermal annealing allowed the conversion of CuC₂ O₄ ⋅x H₂ O to leaf-like CuO nanostructures with a thickness of a few tens of micrometers of sub-sized nanoparticles, which were applied for fabricating binder-free anodes for lithium-ion batteries. Ni was a nucleation site for CuC₂ O₄ ⋅x H₂ O, which was uniformly formed on the entire substrate. The concentration of each component in the mixture solution caused significant morphological changes because of the different elution of copper ions. CuO nanostructures annealed at 550 °C showed large areal and gravimetric capacity with excellent capacity retention of 95.5 % after 200 cycles at a high current density because of their appropriate structural morphology, which not only allowed the formation of a stable solid electrolyte interphase layer but also enabled a reversible reaction during the charge/discharge process.