Fabrication of N-doped Carbon Coated CoFeS2 Anchored rGO Nanosheet Composites: A Twin Carbon Design for Li-ion Storage and High Energy Density Supercapacitor Applications

Abstract

The twin-carbon design represents an innovative strategy to tackle challenges such as insufficient electron/ion transport efficiency, significant volume changes, and various side reactions in various energy-related applications. The present work illustrates the fabrication of N-doped carbon-coated CoFeS2 anchored rGO nanosheet composites for lithium-ion battery and supercapacitor applications. Due to the twin-carbon design, the CoFeS2@rGO/N-C achieves an impressive first charge/discharge capacity of 688.61/838.07 mAh g-1 at 100 mA g-1, with 82.16% of coulombic efficiency. It preserves 82.54 % of initial capacity after 1000 cycles, outperforming both the CoFeS2 and CoFeS2@rGO materials. In supercapacitor tests, the CoFeS2@rGO/N-C demonstrates a specific capacity of 322 mA h g-1 (1933 F g-1) at 1 A g-1, with rate capability of 49 % at 30 A g-1. The CoFeS2@rGO/N-C//activated carbon asymmetric device provides a specific capacity of 176.3 mA h g-1 (352.7 F g-1) at 1 A g-1, along with the 79.4 W h Kg-1 and 16.9 kW Kg-1 of energy and power density values respectively. The asymmetric device shows only a 12% decline in initial capacity and maintains 88% cyclic stability, with 97 % coulombic efficiency after 10,000 continuous cycles at 10 A g-1. Post-study analyses further confirm the high stability of the twin-carbon approach in the CoFeS2@rGO/N-C composite. This research underscores a comprehensive understanding of the twin-carbon strategic design for developing superior electrodes in sustainable energy storage applications.