Access Type

Open Access Thesis

Date of Award

January 2016

Degree Type

Thesis

Degree Name

M.S.

First Advisor

Simon Ng

Abstract

Supercapacitors (SCs) and Li-ion batteries (LIBs) are two types of important electrical energy storage devices with high power density and high energy density respectively. However, to satisfy the increasing demand of high-performance energy storage devices, the energy density of SCs and power/energy densities of LIBs have to be further improved. The exploration, research, and development of electrode materials with high-performance for applications in SCs and LIBs are still needed to meet the ever-increasing demand on energy and power densities. Herein, the amorphous Ni-Co-Mo ternary hydroxides nanoflakes for SCs and oxides nanoflakes for LIBs with ultrathin stature, abundant open spaces, and interconnecting mesoporous were prepared via electrodeposition method and further annealing process, respectively. The as-obtained materials with unique hierarchical structures offer a large electrochemical active area, resulting in a fast ion transportation (OH- in SCs and Li+ in LIBs) electrolyte immersion, as well as provide effective pathways for electron transport. Thus, the as-prepared Ni-Mo-Co triple hydroxides and oxides electrodes exhibit a high specific capacitance /capacity (3074 F g-1 at 2 A g-1 in SCs and 1132.31 mA h g-1 at 0.2 A g-1 in LIBs), remarkable rate performance, as well as long-term cyclability in SCs and LIBs, respectively. Also, the effect of composition of trimetallic hydroxides on SCs performance have been studied, and the performance have been optimized by tuning the feeding ratio of Ni, Mo, and Co. It is found that supreme performance was achieved when feeding ratio Ni/Mo/Co (1/1/0.4).

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