Dual-acting cellulose nanocomposites filled with carbon nanotubes and zeolitic imidazolate framework-67 (ZIF-67)-derived polyhedral porous Co3O4 for symmetric supercapacitors

Conforming to sustainable development trend, natural material cellulose has been extensively studied in the field of energy storage. However, its low conductivity is a huge obstacle to its application in supercapacitors. Integrating nanocellulose as a green binder with conductive materials achieves the efficient use of natural resources. Here, carbon nanotubes (CNTs) were embedded in porous Co3O4 (PCO) dodecahedrons in situ derived from zeolitic imidazolate framework-67 (ZIF-67), for which the morphologies of the composites were considerably remained at the dodecahedron. The main pseudo-capacitive materials are regulated by different amounts of CNTs to modify the morphology and enhance the conductivity. For electrode materials, the charming structure of PCO-CNTs (PCC) with multichannels allows efficient electron transfer, which brings about a competent utilization of redox active sites in PCO. What is more worth mentioning is that the nanocellulose-PCC nanocomposites with good processing properties were used to form binder-free electrodes. Given the fine designed structure and good electrochemical performance, the electrodes were assembled into symmetric supercapacitors, showing high areal capacitance, energy, and power density. The preparation of composites based on PCC and nanocellulose provides a new way to develop sustainable energy storage devices.

Automated summary

By integrating nanocellulose as a green binder with conductive materials, natural material cellulose has been more efficiently used in energy storage applications. Embedding carbon nanotubes in porous Co3O4 derived from zeolitic imidazolate framework-67 has effectively enhanced the conductivity and morphology of the composites.