A universal synthetic route to carbon nanotube/transition metal oxide nano-composites for lithium ion batteries and electrochemical capacitors

• DOI: 10.1038/srep37752
• Publication Date: 2016-11-25T15:32:35Z
• Authors: Han Zhou; Lusi Zhang; Dongyang Zhang; Shuangqiang Chen; Paul R. Coxon; Xiong He; Mike Coto; Hyun-Kyung Kim; Kai Xi; Shujiang Ding
• Keywords: 0306 Physical Chemistry (incl. Structural); FOS: Nanotechnology; 0302 Inorganic Chemistry; Nanotechnology; Bioengineering; 0912 Materials Engineering; 7. Clean energy; 01 natural sciences; Article; 0104 chemical sciences

AbstractWe report a simple synthetic approach to coaxially grow transition metal oxide (TMO) nanostructures on carbon nanotubes (CNT) with ready control of phase and morphology. A thin (~4 nm) sulfonated-polystyrene (SPS) pre-coating is essential for the deposition of transition metal based materials. This layer has abundant sulfonic groups (−SO3−) that can effectively attract Ni2+, Co2+, Zn2+ ions through electrostatic interaction and induce them via hydrolysis, dehydration and recrystallization to form coaxial (NiO, Co3O4, NiCoO2 and ZnCo2O4) shells and a nanosheet-like morphology around CNT. These structures possess a large active surface and enhanced structural robustness when used as electrode materials for lithium-ion batteries (LIBs) and electrochemical capacitors (ECs). As electrodes for LIBs, the ZnCo2O4@CNT material shows extremely stable cycling performance with a discharge capacity of 1068 mAh g−1 after 100 cycles at a current density of 400 mAg−1. For EC applications, the NiCoO2@CNT exhibits a high capacitance of 1360 Fg−1 at current densities of 10 Ag−1 after 3000 cycles and an overall capacitance loss of only 1.4%. These results demonstrate the potential of such hybrid materials meeting the crucial requirements of cycling stability and high rate capability for energy conversion and storage devices.