Sea Urchin Shaped Cobalt Carbonate Hydroxide Hydrate Tribo‐Positive Material for Triboelectric Nanogenerator

ABSTRACT

Triboelectric nanogenerators (TENGs) are emerging as promising technologies for sustainable low‐power energy harvesting, and many researchers are finding advanced materials with tailored surface architectures. Hence, this paper reports the synthesis and structural development of self‐organized hierarchically structured cobalt carbonate hydroxide hydrate (CCHH) as a strong tribo‐positive material for TENG applications. The pure CCHH exhibits a unique sea urchin‐like floral structure composed of ∼1 µm microspheres and 5–8 nm radial nanorods, with a significantly enhanced effective contact area for triboelectrification. The hierarchically structured nanostructures, large surface area, and performance‐optimizing functional groups result in strong tribo‐positive behavior in CCHH, leading to a strong tendency to donate electrons during contact electrification. CCHH‐based TENG delivers high electrical output, peak voltage of ∼654 V, a current of ∼55 µA, and charge density of 98.7 nC m ⁻² at 5 Hz. Furthermore, the device achieved a power density of ∼796 µW cm ⁻² at 7 MΩ load and exhibited excellent stability at ∼312.5 V over 10 000 continuous cycles. The proposed device is also successfully employed to charge commercially available capacitors, light around 120 LEDs, and harvest biomechanical energy. It highlights the applicability of transition‐metal carbonate and hydroxide hydrates as promising tribo‐positive materials for high‐performance, environmentally robust TENGs.