Unveiling the potential of nanosheet-based NiTe2@MnTe hollow nanospheres in hybrid supercapacitor technology

Abstract

In the pursuit of developing superior hybrid supercapacitors, it's vital to secure positive electrode materials that maintain morphological integrity. In this regard, we have successfully synthesized hierarchical NiTe₂@MnTe hollow spheres, adorned with nanosheets, also referred to as NMT-HS. Our method uses a nickel metal–organic framework (NiMOF) for the synthesis of the NMT-HS and these structures are then employed as positive electrode materials for hybrid supercapacitors. The inclusion of tellurium in the formation of the NMT-HS sample noticeably elevates its conductivity. The unique hollow structure of NiTe₂@MnTe, combined with nanosheets, circumvents the typical aggregation and pulverization issues found in nanomaterials while ensuring sustained structural durability through cycling processes. Consequently, the NMT-HS electrode unveils highly desirable electrochemical attributes, including a capacity of 1325.50 C g⁻¹ at 1 A g⁻¹, and a reliable lifespan surpassing 7000 cycles, with only a minor capacity loss of 8.15% at 7.5 A g⁻¹. We have crafted a hybrid device, dubbed (+)NMT-HS//(−)activated carbon (AC), which employs the NMT-HS positive electrode in tandem with the AC negative electrode. This device demonstrated a remarkable energy density of 62.3 W h kg⁻¹, a power density of 890 W kg⁻¹, and displayed substantial longevity (85.75% after 7000 cycles). This evidence underscores the significant potential and wide-ranging application of our uniquely designed electrode material in energy storage systems.