Glucose-Induced NiCo-Based Basic Carbonates Expose Different Crystal Faces for High-Performance Asymmetric Supercapacitors

Opening the layered structure of NiCo-based basic carbonates (NiCoCH) can expose different main crystal faces, thereby exhibiting different electrochemical properties. In this study, the adsorption of glucose by NiCoCH was used to open the layered structure of NiCoCH, which changed the crystal face exposed on the surface of NiCoCH. When 0.05 g of glucose was added, the exposed crystal faces of the prepared NiCoCH-0.05 surface showed the coexistence of amorphous and crystalline structures, which provided a good structural basis for achieving excellent electrochemical properties. The crystal face spacing exposed on the NiCoCH-0.05 surface is 0.215 nm, which is significantly different from that of NiCoCH. Electrochemical tests showed that the specific capacitance (428.4 F g–1 for 1 A g–1), rate performance, and electronic conductivity of NiCoCH-0.05 were all higher than those of NiCoCH (338.6 F g–1 for 1 A g–1). Among them, exposure of the surface crystal faces plays a dominant role in the improvement of the electrochemical properties. The asymmetric supercapacitors (ASC) assembled with NiCoCH-0.05 and activated carbon (AC) have a high energy density of 23.7 Wh kg–1. After 10,000 cycles, the capacitor retention rate is 100%, which shows the potential application value. This work provides a mild and low-cost new strategy for improving the electrochemical properties of transition metal basic carbonates and provides a new theoretical support for the relationship between structure and electrochemical properties.