Nickel/nickel oxide coatings for fiber batteries

• A fiber NiCd battery was demonstrated and evaluated via discharge testing.
• Nickel coatings were applied to glass capillary tubes via electroless plating.
• Bath chemistry, temperature and time were evaluated for the Ni plating process.
• The maximum terminal voltage of the NiCd fiber battery was ∼1.2 V.
• We proposed battery fabrication in random and ordered hole fiber structures.

A Nickel–Cadmium fiber micro–battery design consisting of a nickel/nickel oxide coated glass capillary tube, cadmium micro–wire, and polyimide micro–tube was evaluated in this paper. The nickel/nickel oxide thin films were deposited via electrolysis and the quality was evaluated via the effect of the sulfate concentration, plating temperature, plating solution pH, and heat treatment. The maximum voltage range of the fiber batteries ranged from 0.68–1.2 V, while the maximum current supplied by battery ranged from 0.6–1.0 mA. The results of this work demonstrate the feasibility of fiber batteries that can be readily adapted to random or ordered hole fibers and readily integrated into all-fiber optoelectronic devices.