Development of High Energy-density and High-power Density Lithium-ion Capacitors for Energy Storage Systems

Abstract

Li-ion capacitors (LICs) have gained considerable attention as viable energy storage solutions in the electronics industry. The performance of lithium-ion batteries is mostly controlled by the choice of electrode material, so the careful choice and advancement of electrode materials are of utmost importance. This pivotal aspect necessitates meticulous research to identify electrode materials that can maximize energy storage efficiency. In this study, the fabrication and evaluation of manganese dioxide nanotube (MnO2), manganese dioxide nanotube/graphene oxide (MnO2/GO), manganese dioxide nanotube/carbon nanotube (MnO2/CNT) and manganese sulphide/graphene oxide (MnS/GO) composite electrode materials were investigated.

In this work, manganese dioxide nanotubes and MnO2/GO composite electrode materials were fabricated. The fabrication process employed is characterized by its simplicity, cost effectiveness and environmentally benign nature. The resulting architecture exhibits a distinctive structural arrangement wherein the MnO2 nanotubes are enveloped by the GO nanosheets. The MnO2/GO composite anode, when utilized in conjunction with a binder-free buckypaper technique, exhibits exceptional electrochemical characteristics, including elevated energy and power density, improved rate capability and superior cyclic stability. The results obtained in this study demonstrate the potential of the MnO2/GO composite anode for use in lithium-ion battery (LIB) applications. Manganese dioxide nanotube/carbon nanotube (MnO2/CNT) composites were also used in another study as part of a larger effort to find better electrode materials for LICs. The fabrication of MnO2/CNT electrodes was achieved through a well-defined process, harnessing the synergistic properties of MnO2 nanotubes and carbon nanotubes. These electrodes were integrated into a similar binder-free buckypaper configuration for enhanced charge transfer kinetics and structural integrity. Comprehensive electrochemical assessments, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS), were conducted to evaluate the performance of MnO2/CNT composite electrodes. The results demonstrated noteworthy energy storage capabilities, reinforcing the potential of MnO2/CNT composites as a compelling electrode material choice for high-performance LICs, further contributing to the development of efficient energy storage solutions in the electronic industry.

In parallel, we extend our investigation to the fabrication and evaluation of MnS/GO composite electrode material. Similar to the MnO2/GO fabrication process, a simple, effective hydrothermal technique was employed to create the MnS/GO composite. This technique resulted in manganese sulphide (MnS) nanoparticles/crystals with GO nanosheets, yielding a distinctive architecture that leverages the synergistic interplay between the two components. The fabricated electrode material was then integrated into a binder-free buckypaper framework to ensure enhanced charge transfer kinetics and structural robustness.

Electrochemical evaluations were conducted using CV, GCD and EIS measurements for all samples of MnO2, MnO2/GO, MnO2/CNT and MnS/GO composite electrodes. The obtained results demonstrated the substantial energy storage capabilities of both composite electrode materials. The MnO2/GO and MnO2/CNT composites exhibited encouraging energy and power densities, along with a commendable rate capability and sustained cyclic stability. A comparison of the performance metrics of all samples of MnO2, MnO2/GO, MnO2/CNT and MnS/GO is presented at the end of the study. We elucidate the potential of each to serve as an alternative electrode material for high-performance LICs and LIBs.

Date of Award	27 Dec 2023
Original language	American English
Supervisor	Al Marzooqi (Supervisor)