Two-dimensional ultra-thin CuCoNiMnAl high-entropy alloy nanosheets for lithium-ion storage and oxygen evolution reaction

High entropy alloys (HEAs) are a new class of materials. Utilization of the HEAs concept in the fabrication of sophisticated functional materials has the potential to achieve highly effective energy storage and conversion . In this work, we have successfully fabricated a two-dimensional ultra-thin nanosheet structure of CuCoNiMnAl high-entropy alloy (HEA) utilizing a simple salt-templated method, marking the first instance of such synthesis. The findings indicate that the inclusion of sodium chloride can proficiently enhance the development of a nanosheet configuration, while the distinct variations in annealing temperature impact the characteristics of the substances. As an illustrative instance, the CuCoNiMnAl high-entropy alloy nanosheets, which have undergone annealing at a temperature of 800 °C, demonstrate exceptional characteristics in terms of lithium-ion storage and electrocatalytic capabilities for the oxygen evolution reaction (OER). These nanosheets possess a reversible capacity of approximately 700 mAhg −1 at 100 mA g −1 after 80 cycles, along with a low overpotential (390 mV) and Tafel slope (65 mV dec −1 ) at a current density of 10 mA cm −2 for OER. Additionally, they exhibit long-term durability in electrochemical performance , with only negligible decay in an alkaline environment. Our work provides a new idea for the design and application of novel HEAs in the field of energy.