Development of nickel-based cable batteries with carbon nanotube and polytetrafluoroethylene enhanced flexible electrodes

The fabrication of flexible nickel-based cable batteries is presented. Different fabrication methods, as well as formulations, were studied. It was found that iron anodes were more suitable than zinc electrodes for the helix design used in the cable/rope-shaped cells, possibly due to their higher stability in the alkaline environment. Furthermore, the addition of a thin polytetrafluoroethylene (PTFE) layer to the electrodes enhanced their mechanical stability, making them more durable and stable when twisted into helixes during cell assembly and packaging. A single-step precipitation reaction was used to load iron oxides directly onto carbon nanotubes, which promoted contact between iron/iron oxide particles and conductive additives and thus improved the discharge capacity of the batteries. After optimizations, the typical iron anode showed initial specific capacity higher than 90 mAh g⁻¹, though it decreased to around 60 mAh g⁻¹ and remained more stable as cycles continued. The cable cells also remained functional and showed consistent performance under bent conditions.