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Title: Hybrid Li-air battery cathodes with sparse carbon nanotube arrays directly grown on carbon fiber papers

Sparsely populated, vertically aligned nitrogen doped carbon nanotube arrays (CNTAs) with dislocated-graphene stacking were grown directly on carbon fiber papers and investigated as hierarchical air cathodes in hybrid Li-air batteries with aqueous catholytes. The CNTAs were made with electrodeposited Ni nanocatalysts, followed by plasma-enhanced chemical vapor deposition. The thus obtained CNTAs can reach a population number density as low as similar to 10(7) per cm(2) on the carbon fibers, achieving an extremely high porosity of over 99% for the active layer in the cathode. The sparse CNTAs not only provide effective pathways for the reacting species, but also show a significantly high catalytic activity, which is found to be comparable to that of a supported Pt electrocatalyst. The high activity of the CNTAs is attributed to the rich graphene edges exposed on the CNT surface and nitrogen doping. Hybrid Li-air batteries with such cathodes have shown a consistent discharging capacity of 710 mA h g(-1) and a specific energy of 2057 W h kg(-1) at 0.5 mA cm(-2). Stable charge-discharge cycling at 0.5 mA cm(-2) showed an average potential difference of 1.35 V, indicative of a relatively small overpotential and high round trip efficiency (71%). Furthermore, the hybrid Li-air batterymore » based on the hierarchical cathode can reach a power density as high as 10.4 mW cm(-2).« less
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Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Energy & Environmental Science; Journal Volume: 6; Journal Issue: 11
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Country of Publication:
United States