Integrating the essence of metal organic framework-derived ZnCoTe–N–C/MoS2 cathode and ZnCo-NPS-N-CNT as anode for high-energy density hybrid supercapacitors

Abstract

Transition bimetallic compounds are exploited as high-capacity electrode materials for supercapacitors due to their abundant electroactive sites and electrical conductivity. However, it remains grand challenge to construct supercapacitor devices that deliver high energy density. Here, we report an attractive one-stone-two-birds strategy to develop metal organic frameworks (MOFs) derived cathodes and anodes consisting of zinc cobalt telluride integrated nitrogen doped carbon (ZnCoTe–N–C) and zinc cobalt nanoparticles encased nitrogen doped carbon nanotubes (ZnCo-NPs-N-CNTs), respectively. Particularly, ZnCoTe–N–C cathode exhibited high specific capacity of 192.77 mA h g−1, which was further improved by the presence of hierarchical molybdenum disulfides (MoS2) nanosheets. Increased electrochemical active sites provided by MoS2 nanosheets energizes both the capacity and stability of the electrode. Consequently, the ZnCoTe–N–C/MoS2 electrodes showed a higher specific capacity of 342.55 mA h g−1 as well as excellent long-term stability. Besides, the ZnCo-NPs-N-CNTs demonstrated an initial capacity of 207.22 mA h g−1 and retained a high specific capacity even after 50 A g−1. The excellent electrochemical activity of the electrodes is attributed to the incorporation of redox rich bimetallic components and nitrogen rich carbon directly grown on the current collector, which reduces the dead volume and avoids volume expansion during charge discharge process. Finally, a hybrid asymmetric supercapacitor (HASCs) assembled using ZnCoTe–N–C/MoS2 and ZnCo-NPs-N-CNTs delivered a high specific energy density and power density maintaining 93.6% of its capacitance after 20,000 cycles. This study expands a way to construct a hybrid supercapacitor with well-designed structure and superior performance for clean energy storage technologies utilizing minimum resources.