Nickel-cobalt (oxy)hydroxide battery-type supercapacitor electrode with high mass loading

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-02, Vol.429, p.132423, Article 132423
• Main Authors: Gao, Mingyuan, Li, Yating, Yang, Jinhu, Liu, Yuexin, Liu, Ying, Zhang, Xiaoxiao, Wu, Shuanghao, Cai, Kefeng
• Format: Article
• Language: English
• Subjects: Areal capacity; Electrochemical activation; Mass loading; NiCo-LDH; Supercapacitor
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.132423

•NiCoOOH composite was prepared by an in-situ electrochemical activation method.•The optimal electrode achieves an exceptionally high areal capacity and mass loading.•Areal capacity increases linearly by systematically tuning the pore sizes.•Volumetric capacity remain unchanged with increasing mass loading.•The electrode yields a record energy density of 19.1 mWh cm−2. Transition metal hydroxides have shown high capacity performances when at a small mass loading of active material, while it is still a great challenge to obtain a high capacity performance when the mass loading is high. To maximize the capacity at high mass loading, the microstructure of the electrode should be rationally designed. Herein, we report a nickel–cobalt (oxy)hydroxide composite with three-dimensional hierarchical porous architecture realized by an in-situ electrochemical activation method to trigger the active sites and structural rearrangement. By systematically tuning the pore sizes in the hierarchical structure, an optimal composite delivers a record high areal capacity (34.8 mAh cm−2) and energy density (19.1 mWh cm−2) at the mass loading up to 230 mg cm−2. It gives new insights for preparing high performance electrode materials by a facile method and provides a blueprint for the design of high mass-loading supercapacitors.