A Review on the Application of Cobalt-Based Nanomaterials in Supercapacitors

Among many electrode materials, cobalt-based nanomaterials are widely used in supercapacitors because of their high natural abundance, good electrical conductivity, and high specific capacitance. However, there are still some difficulties to overcome, including poor structural stability and low power density. This paper summarizes the research progress of cobalt-based nanomaterials (cobalt oxide, cobalt hydroxide, cobalt-containing ternary metal oxides, etc.) as electrode materials for supercapacitors in recent years and discusses the preparation methods and properties of the materials. Notably, the focus of this paper is on the strategies to improve the electrochemical properties of these materials. We show that the performance of cobalt-based nanomaterials can be improved by designing their morphologies and, among the many morphologies, the mesoporous structure plays a major role. This is because mesoporous structures can mitigate volume changes and improve the performance of pseudo capacitance. This review is dedicated to the study of several cobalt-based nanomaterials in supercapacitors, and we hope that future scholars will make new breakthroughs in morphology design.

Approaching high performance Ni(Co) molybdate electrode materials for flexible hybrid devices

Transition metal molybdates are widely used as electrode materials for supercapacitors due to their high theoretical specific capacitance and excellent electrochemical activity. It is an effective strategy to improve the electrochemical performance by reasonably designing electrode materials. Herein, we prepared several Ni_1-xCo_xMoO₄·nH₂O nanostructures through facile hydrothermal strategies. Benefiting from the synergistic effects between Ni and Co elements, the obtained electrode materials delivered a specific capacitance of 1390 F g⁻¹ at 1 A g⁻¹. The as-assembled device shows an energy density of 72.45 W h kg⁻¹ at a power density of 2688.8 W kg⁻¹. It also presents excellent cycling and mechanical stability after many times of charging and discharging processes and bending.

We prepare several Ni_1−xCo_xMoO₄·nH₂O nanostructures through facile hydrothermal strategies. The obtained electrode materials delivered a specific capacitance of 1390 F g⁻¹ at 1 A g⁻¹. The as-assembled device shows an energy density of 72.45 W h kg⁻¹ at a power density of 2688.8 W kg⁻¹.