Compositionally variant bimetallic Cu–Mn oxysulfide electrodes with meritorious supercapacitive performance and high energy density

Abstract

Rational design and fabrication of low-cost, earth-abundant electrode materials for energy conversion and storage devices is immensely needed. Herein, we demonstrate the successful fabrication of Cu–Mn mixed-metallic oxysulfides (Cu–Mn–OS) and their use as supercapacitor electrodes, benefiting from the integrated advantages of both oxides and sulfides as well as the combined contribution from both Cu and Mn elements. In particular, the C₃M₁OS electrode performs exceptionally well in a three-electrode system, revealing a very high capacity of 1525.1 C g⁻¹ (3177.2 F g⁻¹) at a current density of 1 A g⁻¹. Moreover, using commercial activated carbon (AC) as the negative pole and a C₃M₁OS electrode as the positive pole, the fabricated asymmetric supercapacitor device (C₃M₁OS//AC) exhibits a very high energy density of 76.56 W h kg⁻¹ along with a power density of 985.01 W kg⁻¹ at 1 A g⁻¹ with superior electrochemical stability and efficiency over 10 000 cycles. The current work not only proposes a straightforward, single-step strategy for the fabrication of mixed-metallic oxysulfide electrodes but also establishes a new avenue for the fabrication of a standout candidate electrode for energy storage devices with a distinctive specific energy.