A high-energy-density zinc/iodine-bromide redox flow battery (ZIBB) has recently been developed by Prof. Yi-Chun Lu, Assistant Professor of the Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong and her research team. ZIBB achieved the highest reported energy density for aqueous redox flow batteries to-date. The breakthrough was published in the renowned journal Energy & Environmental Science in early 2017, and was recently featured by the magazine Chemistry World, published by The Royal Society of Chemistry, United Kingdom.

Bromide ion (Br-): The Key to Releasing Energy Density

Aqueous Redox Flow Battery (RFB) is a device that generates electricity by electron transfer between two electrolytes. RFB is safe, friendly to the environment, with high design flexibility and long life (several decades), and it appears to have a high commercialization potential. With the introduction of Bromide ions (Br-), Professor Lu’s research group boosted the energy density of ZIBB to as high as 101 Wh L^-1, achieving the highest reported energy density to-date, i.e. an improvement of at least 20% in capacity relative to a control system.

In zinc/iodine RFBs, highly soluble zine iodide is the major active material in the electrolyte, with iodide ions (I-) and zinc (Zn) being the electrochemical active ingredients at the positive and negative electrodes respectively. Free iodine (I₂) is present in the battery, and iodide ions (I-) act as the stabilizing agent to form triiodide ions (I_3-), thereby stabilizing the cycle life of the battery (efficiency as high as 95% over 50 cycles). However, the power of the iodide ions (I-) in contributing battery capacity is wasted as they are “trapped” as a stabilizing agent.      

The group therefore pioneered the innovation by which bromide ions are introduced as a replacement for the “trapped” iodide ions (I-), i.e. forming iodine bromide ions (I₂Br_-) by reacting bromide ions (Br-) with iodine (I₂). The process still allows a stable cycle life in the battery, without sacrificing energy capacity.  

The Potential of ZIBB

This new energy storage system with high energy density and a stable cycle life has  potential in the growing market for electric cars. “The price of electric cars would be significantly lowered if this type of battery was adopted, with much longer driven mileage. Moreover, this type of battery is much safer as in a regular crash. Some work in commercializing the technology is underway. The technology is promising when applied to higher performing, lower cost, and larger scale energy storage systems.” Professor Lu commented.

Their experiment also proved that the technology is able to boost the theoretical energy density of all electrochemical energy storage systems that involve iodine by one third. In the future, the team is going to research further into low-cost and high-performance electrode and membrane materials to optimize the technology.

About the Research Project “Smart Solar Energy Harvesting, Storage and Utilization”

The study is part of the 5-year research project “Smart Solar Energy Harvesting, Storage and Utilization” led by Prof. Ching-ping Wong, Dean of Engineering, CUHK. The project has been funded by the Theme-based Research Scheme (TRS) of the Research Grants Council (RGC) of the Hong Kong Government (HK$ 60.33 million) since 2014, with another HK$ 13.8 million from CUHK and HK$ 3 million from other partner universities. More than 30 scholars from CUHK, The Hong Kong Polytechnic University, The Hong Kong University of Science and Technology and The University of Hong Kong have been working together to enhance the efficiency of solar power and the penetration of the technology.

About Prof. Yi-Chun Lu

Prof. Yi-Chun Lu received her B.S. degree in Materials Science & Engineering from the National Tsing Hua University, Taiwan, in 2007. She received her Ph.D. degree in Materials Science & Engineering from the Massachusetts Institute of Technology (MIT), Cambridge, USA in 2012. Professor Lu has been appointed as a research affiliate of MIT since 2013. She is currently an Assistant Professor in the Department of Mechanical and Automation Engineering at CUHK. Professor Lu has been conferred various CUHK and international research and teaching awards, including the University Education Award, CUHK (2016), the Vice-Chancellor's Exemplary Teaching Award, CUHK (2014), the Early Career Award, Research Grant Council, Hong Kong SAR (2014), Massachusetts Institute of Technology Martin Family Society of Fellows for Sustainability (2009) and the Taiwan National Science Council Outstanding Research Innovation Award (2007).

A team of students from the Department of Mechanical and Automation Engineering won the Champion in the 6th Greater China Design Competition.　

Hosted by the Institution of Mechanical Engineers (IMechE) Hong Kong Branch, the competition was held in the Hong Kong University of Science and Technology, Hong Kong, on 25 to 26 March 2017.  The theme is to design, build, and perform test runs for an energy conversion system to utilize the gravitational potential energy stored in two liters of water to lift as much simulated ore as possible out of the simulated mine and deposit it into a receiving bin.

The CUHK team, led by Dr. LI Yiyang, Prof. XU Dongyan and the assessor LEUNG Yun Yee, has competed among eight teams from universities in Hong Kong, Macau and mainland.  With its innovative design ideas, and excellent demonstration, CUHK team won the Champion.

The team comprises of the following eight students:

YIP Kwan Yi, YIP Ka Chun, YIP Chi Yiu, CHIU Sin Hang, HO Wing Hang, LEUNG Chun Hei, CHOW Ka Chung, YUE Felix Yun Fei

The Fauclty has nutured over sixteen thousands of engineering professionals since its inception. All of the selected alumni comes from different fields but have set a very good role models to the Faculty.  Professor WONG Ching Ping, Dean of Engineering expressed his congratulations to the alumni and said in the ceremony, "With a history of 25 years, the Faculty is committed to the education of future leaders in technology, the betterment of engineering curriculum, and the application of technology to meet the human and societial needs. We are delighted to salute the 25 distinguished alumni and also hope our future generations will be enlightened to make a difference with their Engineering skills and knowlegdge." 

The selection panel comprise the Distinguished Professor-at-Large YAO Chi-chih Andrew from the Department of Computer Science and Engineeirng, Professor CHING Pak Chung from Department of Electronic Engineering, Professor YEUNG Wai Ho Raymond from Department of Information Engineering, Professor YAM Yeung, Department of Mechanial and Automation Engineering, and Prof. WONG Kam Fai,  Department of Systems Engineering and Engineering Management. 

The list of awardees for Distinguished Alumni is as follows (in alphabetical order):

Prof. Cliff C. K. CHAN

Chairman, TeleEye Founders' Charity Foundation Ltd

for his contribution in video surveillance technology and technology transfer

Mr. CHAU Stephen

Chief Technology Officer, SmarTone

for his contribution to the development of mobile communications in Hong Kong

Prof. CHING Wai Ki

Department Head and Professor, Department of Mathematics, The University of Hong Kong

for his leadership in mathematics education and contribution to research in stochastic modeling and matrix computations

Prof. CHOI Tsan Ming Jason

Professor of Fashion Business, Institute of Textiles and Clothing, The Hong Kong Polytechnic University

for his contribution in operations management, especially in supply chain management for fashion business operations

Dr. DAI Ruoli Tristan

Co-Founder and Chief Technology Officer, Noitom Ltd.

for his contribution to the motion capturing technology and leadership in the relevant industries

Dr. HE Kaiming

Research Scientist, Facebook

for his contribution to the advancement of the art and science of artificial intelligence

Prof. HO King Choi

Professor, College of Engineering, University of Missouri, USA

for his research and educational contribution to signal processing and wireless networks

Dr. LAM Hiu Fung Alan

Chief Executive Officer, Sengital Limited

for his contribution to the innovation and technology industry and to entrepreneurship education

Prof. LAU Chong Fuk

Professor and Division Head, Department of Philosophy, CUHK

for his excellence in teaching and research in German philosophy, a field beyond his original training in engineering

Mr. LEE Wai Kwong

Chief Executive Officer, ASM Pacific Technology Ltd.

for his leadership in the electronic industry

Mr. LEE Ying Ho Tim

Co-founder and CEO, QFPay

for his contribution to the development of mobile payment technology in China

Ms. LEE Yuk Chun Eppie

Senior MI Manager - Business Process Control Asia (Finance - COO), HSBC

for her leadership in the banking sector and contribution to the community, including areas such as charity, education and environment

Mr. LEUNG Kin Man Michael, MH

Chief Information & Operations Officer, China CITIC Bank International Limited

for his contribution to the IT development in Hong Kong

Mr. NG Hin Kwong Benson

Partner, Ernst and Young

for his contribution to information systems analysis and design in the international business sector

Mr. NG Kwok Sing Aldous
CEO, Unissoft Technology Co.Ltd.

for his contribution to the development of information and data management technology in Hong Kong

Prof. SUN Dong

Chair Professor and Head, Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong

for his contribution to robot-aided manipulation of biological cells

Dr. TAM Wai Ho Samson

Founder and Chairman, Group Sense Ltd.

for his leadership in electronic industry and contribution to the development of IT in Hong Kong

Mr. TONG James

Director of Public Affairs, John Swire & Sons (H.K.) Ltd.

for his leadership in the aviation and contribution to tourism and retail industries of Hong Kong

Dr. WONG Chak Kei

Managing Director, Societe Generale Corporate & Investment Banking

for his leadership in the banking industry and contribution to the society

Mr. WONG Kwan Wai Sammy

Head of Operating, West Region, MTR

for his contribution to metro subway transportation in Hong Kong

Prof. WONG Pak Kin

Professor of Biomedical Engineering, Mechanical Engineering and Surgery, Department of Biomedical Engineering, The Pennsylvania State University, USA

for his contribution to engineering research and education in translational laboratory science and technology for life sciences and medicine

Prof. WONG Tak Sing

Assistant Professor of Mechanical Engineering, Wormely Family Early Career Professor in Engineering, Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, USA

for his contribution to the field of biologically inspired surface nanoengineering

Mr. WONG Wai Kay Ricky

Chairman, Hong Kong Television Network Limited

for his leadership in the information and communication industry

Dr. XU Yabo Arber

Chief Executive Officer, Interactive Data Technology Ltd (IDT) 

for his contribution to big data technology

Prof. YANG Yang

Director of Key Laboratory of Wireless Sensor Network and Communication,

Director of Shanghai Research Center for Wireless Communications

for his contribution to wireless communications