Postdoctoral Fellow, the University of Hong Kong
A printable Al-air battery on paper for miniwatt applications
Yifei Wang (1,*), Holly Kwok (1), Wending Pan (1) and Dennis Y.C. Leung (1)
(1) Department of Mechanical Engineering, the University of Hong Kong, Hong Kong, China
Metal-air battery is a fascinating energy technology because of its superior energy density , among which Al-air battery is especially advantageous considering its low cost, high specific energy and environmental friendliness . Currently, most Al-air batteries employ Al block or Al plate as anode, while a printable Al-air battery using Al ink has never been reported to the best of our knowledge. In this work, we have explored the feasibility of this idea by developing an Al ink for its anode fabrication. This Al ink was developed by dispersing micro-scale Al particles into ethanol solvent solution, together with carbon nanotubes (CNT) as current collector and carboxymethyl cellulose (CMC) as binder. As for the air-breathing cathode, the ink for oxygen reduction reaction (ORR) was prepared by dispersing MnO2 supported on CNT in ethanol solvent solution together with a Nafion binder. Afterwards, the printable Al-air battery was simply fabricated by depositing Al ink and ORR ink with specific loadings onto the opposite sides of a paper substrate, respectively, as shown in Fig. 1(a). When tested with 4 M NaCl as electrolyte at room temperature, the present printable Al-air battery could achieve an OCV of 0.8 V, a peak power density of 2 mW cm-2 and a maximum current density of 10 mA cm-2 (Fig. 1(b)). In addition, its continuous discharge behavior was exhibited in Fig. 1(c), which could discharge for 5 hours with only 6 mg of Al. The corresponding Al specific capacity was as high as 814 mA h g-1. In conclusion, the present printable Al-air battery is especially suitable for powering various single-use devices with low power requirement, such as point-of-care assays, biosensors, RFID tags, etc., and its power output and energy capacity can be customized by simply tailoring the printing parameters.
 M.A. Rahman, X. Wang, C. Wen, Journal of The Electrochemical Society, 160 (2013) A1759-A1771.
 Y. Liu, Q. Sun, W. Li, K.R. Adair, J. Li, X. Sun, Green Energy & Environment, 2 (2017) 246-277.
Dr. Yifei Wang received his BSc degree from the Department of Modern Mechanics, University of Science and Technology of China in 2012, and his PhD degree from the Department of Mechanical Engineering, the University of Hong Kong in 2016. Afterwards, he has been working as a postdoctoral fellow in the University of Hong Kong till date. His research interest is mainly focused on electrochemical energy conversion technologies such as fuel cells, metal-air batteries, aluminum ion battery and electrolyzers, including both experimental study and numerical investigation. Till now, he has published more than 20 papers and filed two patents in these areas. In addition, he has given multiple speeches on his research in both international conferences and invited seminars. His future research will be focused on flexible and printable fuel cells and batteries, redox flow batteries, and rechargeable Al ion battery.
The University of Hong Kong, Asia’s Global University, delivers impact through internationalisation, innovation and interdisciplinarity. It attracts and nurtures global scholars through excellence in research, teaching and learning, and knowledge exchange. It makes a positive social contribution through global presence, regional significance and engagement with the rest of China.