Nanostructured Cobalt Oxide Directly Grown on Carbon Cloth for High-Capacity Lithium-Ion Battery Electrodes

Abstract

Nowadays, with the breakthrough development of various smart devices and electric vehicles that require a large power supply, rechargeable lithium-ion batteries are the most attractive energy storage system because of their high energy density and long lifetime by low self-discharge rate and no memory effect [1,2]. However, due to ever-increasing demands for rechargeable batteries with higher energy density, it is necessary to develop suitable electrode materials to satisfy the sufficient capacity and energy density required for large-scale energy storage systems [3]. As a commercial lithium-ion battery anode, graphite is widely used due to its low operating potential and high stability. However, it cannot fulfill the considerable demands of large-scale energy storage owing to its low practical capacity. As alternatives, transition metal (TM; Mn, Fe, Co and Ni) oxides have attracted great attention due to their high capacity. In this work, we develop the cobalt oxide (Co3O4) with attractively nanostructured architectures (nanowire, nanosheet) directly grown on carbon cloth substrate by a facile hydrothermal reaction followed by heat treatment process. For this, first, Co(NO3)2 and urea are dissolved in deionized water, and then carbon cloth is immersed in the solution. During the hydrothermal reaction, Co2(OH)2CO3·xH2O nanowires or Co2(OH)2CO3 nanosheets are grown on carbon cloth at 90 or 120 °C, respectively. After thermal treatment at 350 °C for 1 h in furnace, Co3O4 nanowires or nanosheets can be obtained. When tested as anodes for LIBs, as-fabricated electrodes without any conductive agents and polymeric binders exhibit high specific capacity because of their large specific surface area and enough space to buffer the volume change during conversion reaction. Therefore, it is considered that these high-performance electrodes can be used as high-capacity anodes for large-scale energy storage system.