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

Journal Article · Fri Nov 01 00:00:00 EDT 2013 · Energy & Environmental Science

DOI:https://doi.org/10.1039/c3ee41116h· OSTI ID:1211256

Li, YF; Huang, ZP; Huang, K; Carnahan, D; Xing, YC

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 battery based on the hierarchical cathode can reach a power density as high as 10.4 mW cm(-2).

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: DE-AR0000066
• OSTI ID: 1211256
• Journal Information: Energy & Environmental Science, Vol. 6, Issue 11; ISSN 1754-5692
• Country of Publication: United States
• Language: English