Lithium batteries are widely used in electric vehicles and electronic products, but concerns are growing about their environmental impact during mining and disposal. Scholars from Lingnan University’s School of Interdisciplinary Studies and their collaborators have published a pioneering study online in top-tier, peer-reviewed, scientific journal Advanced Energy Materials. The study introduces a novel “anode-free sodium battery” that, by tuning the salt concentration in the electrolyte, reduces the risks of short circuits and shortened lifespan during fast charging. Laboratory tests have demonstrated that this new type of battery can be charged within minutes while maintaining safety and stability.
Charging and discharging processes of anode-free sodium batteries. During charging, sodium (Na) metal is deposited on the aluminium (Al) current collector, and during discharging, sodium returns to the cathode.
In recent years, the academic sector has actively explored anode-free sodium batteries (also known as reservoir-free sodium batteries) as a potential alternative to lithium batteries (Photo 1). A major barrier to commercialisation, however, has been the inherent softness of sodium, an alkali metal that makes these batteries prone to short circuits and rapid capacity loss under fast-charging conditions.
Sodium deposition under conditions dominated by charge transfer and sodium-ion diffusion. Under charge-transfer-dominated conditions with sufficient Na+ supply, sodium metal deposits uniformly on the Al current collector. Under diffusion-dominated conditions, where the Na+ supply is insufficient, sodium metal deposits non-uniformly, leading to short circuits.
The joint research team from Lingnan University, Tsinghua University, and the Beijing Institute of Technology identified the critical step governing the stability of sodium batteries: the kinetics of sodium ion deposition. By increasing the electrolyte salt concentration appropriately, the team successfully shifted the deposition process from a diffusion-controlled mode to a charge-transfer-controlled mode (Photo 2), which minimises the risks of short circuits, thereby improving battery stability and lifespan. Additionally, since the fully discharged anode-free sodium battery contains no metallic sodium, production and transportation are safer.
Laboratory experiments confirm that increasing the electrolyte salt concentration ensures a better supply of sodium ions and enables smoother deposition. The critical current density for sodium deposition was enhanced to over 20 mA cm⁻², and the batteries demonstrated a fast-charging capability of 10C, completing charging within minutes, much faster than the typical 1C to 2C charging rate of commercial lithium-ion batteries. Moreover, the cells maintained over 70 per cent of capacity after 500 charge–discharge cycles.
The research team noted that this breakthrough provides valuable insights into the design of safe and stable anode-free sodium batteries, laying the groundwork for future applications. They hope to extend their findings beyond laboratory-scale prototypes to larger applications in electric vehicles, renewable energy storage such as wind and solar power, and consumer electronics.
Prof Li Liangliang, Associate Professor of the School of Interdisciplinary Studies at Lingnan University and co-corresponding author of the research paper.
Prof Li Liangliang, Associate Professor of the School of Interdisciplinary Studies at Lingnan University and co-corresponding author of the research paper , explained “Global society relies heavily on electric vehicles and electronics, yet lithium resources are limited, costly, and unevenly distributed, with extraction processes that damage land and water. Our new anode-free sodium battery replaces lithium with sodium, a more abundant and affordable resource. Sodium costs less than a tenth of lithium, is plentiful in seawater, and can significantly reduce the price of electric vehicles and energy storage systems. Its extraction is also simpler, more sustainable, and less environmentally damaging for the green economy.”
Prof Li Liangliang also pointed out that the research aligns with Hong Kong’s carbon neutrality and electric mobility goals, and that “This study responds to urgent global and local needs in energy transition. The technology has the potential to support greener and more affordable mobility solutions, while reducing dependence on imported lithium.”
Lingnan University has in recent years conducted interdisciplinary research and innovation projects addressing global challenges such as climate change and the clean energy transition. This collaborative research, combining expertise in materials science, chemical engineering, and mechanical engineering, also follows United Nations’ Sustainable Development Goals on “Affordable and Clean Energy” (SDG 7) and “Climate Action” (SDG 13).
Lingnan University continues to participate in annual innovation and technology event the InnoCarnival 2025 (the Carnival), organised by the Innovation and Technology Commission (ITC). As one of the programme partners, Lingnan University is showcasing eight innovative "Smart Healthy City" research projects, integrating artificial intelligence (AI) and interdisciplinary research. These projects cover healthcare, transportation, sports training, environmental monitoring, and elderly care, and demonstrate how Lingnan's innovation teams address societal needs and advancing smart city development through technology.
The Carnival runs from now until 26 October at the Hong Kong Science Park. At Lingnan's exhibition booth (D08), scholars and staff explain how these AI-driven innovations enrich daily life, improve urban liveability, and spark public interest in cutting-edge technology, so that visitors can enjoy multiple interactive experiences.
Prof Sun Dong, Secretary for Innovation, Technology and Industry, visited Lingnan University's booth this afternoon, 18 October, where Prof Sam Kwong Tak-wu, Associate Vice-President (Strategic Research) and J.K. Lee Chair Professor of Computational Intelligence, showed him Lingnan's trailblazing research achievements, saying "In recent years, Lingnan University has actively promoted AI and interdisciplinary research projects to address pressing societal challenges and enhance the quality of life. The eight projects here allow visitors to experience how advanced technology supports the development of a smart and healthy city, demonstrating its profound impact on society.”
Prof Sam Kwong Tak-wu showed Prof Sun the AI-based Fencing Training and Assessment System, co-developed with Prof Zhou Yu of Shenzhen University. The system acts as an AI personal coach, combining smart bracelets and insoles with a motion-sensing camera to observe and analyse fencers' actual movements, enabling scientific training improving safety and efficiency. An interactive fencing zone at the booth allows visiting students to "try it out" in fencing gear and smart bracelets, with motion-sensing cameras performing the fencing movements. Deep learning AI analyses each action, and provides suggestions for improvement, and the project won a Gold Medal and the Prize of the International Federation of Inventors' Association (IFIA) at the 11th Silicon Valley International Invention Festival 2025.
Hong Kong continues to report new cases of chikungunya fever, and Prof Paulina Wong Pui-yun, Head and Associate Professor (Presidential Early Career Scholar) of the Science Unit, showed the AI Mosquito Diseases Control System, displaying various species of mosquitoes recently captured in Hong Kong. Prof Wong also explained how the system's simultaneous map-based mosquito risk index helps people understand mosquito risks in different areas of Hong Kong, raising awareness about preventing mosquito-borne diseases.
Other Lingnan research projects on display include the Subway Passenger Flow Prediction Model, developed by President S. Joe Qin, President and Wai Kee Kau Chair Professor of Data Science, and Dr Liu Yiren, Postdoctoral Fellow of the Division of Industrial Data Science of the School of Data Science; the Direct Air Capture of CO2 to Enrich Agriculture Production project led by Prof Chen Xi, Dean of the School of Interdisciplinary Studies and Chair Professor of Interdisciplinary Studies; the Emergency Baby Incubator and AI Power-assisted Wheelchair Control System projects led by Prof Albert Ko, Director of the Office of Service-Learning and the Lingnan Entrepreneurship Initiative (LEI); the AI Road Risk Monitoring System developed by Prof Paulina Wong Pui-yun, Head and Associate Professor (Presidential Early Career Scholar) of the Science Unit; and the Smart Ageing Home Safety Monitoring System, developed by a team of postgraduate students led by Dr Chloe Siu Pui-yee, Senior Lecturer of the School of Graduate Studies. (Table 1).
For more details, please visit https://innocarnival.hk/en.
Project title Subway Passenger Flow Prediction Model
Scholars Prof S. Joe Qin, President and Wai Kee Kau Chair Professor of Data Science
Dr Liu Yiren, Postdoctoral Fellow of the Division of Industrial Data Science of the School of Data Science
Description This project predicts passenger outflow accurately at different stations in a transportation system and a visualisation interface. Its model of passenger travel time and destination station distribution is based on past passenger gate card swipe data, combined with real-time entry flow data. Multi-time-scale modelling distribution predictions can be made a day in advance, and real-time data adjusts these forecasts dynamically, improving accuracy. The invention also integrates artificial intelligence agents to capture hotspot events, enabling real-time monitoring and prediction of subway passenger flow, and assisting in operational scheduling and resource optimisation, which improve the efficiency of the entire transportation system.
Project title AI-based Fencing Training and Assessment System
Scholar Prof Sam Kwong Tak-wu, Associate Vice-President (Strategic Research) and J.K. Lee Chair Professor of Computational Intelligence
Description The smart fencing training system is an intelligent AI personal fencing coach, which uses smart sensors in bracelets and insoles and a motion-sensing camera to watch and analyse a fencer's movements in real time. Unlike older systems that just recognise basic actions, this understands the quality of each move, and can tell if a lunge is well-balanced, a step is efficient, or a strike is powerful. AI supports fencers' physical health, skills, and overall enjoyment of the sport, making training smarter, safer, and more available to fencers.
Project title Direct Air Capture of CO2 to Enrich Agriculture Production
Scholar Prof Chen Xi, Dean of the School of Interdisciplinary Studies and Chair Professor of Interdisciplinary Studies
Description The research team has developed a novel material to be used in carbon farming that captures CO2 directly from the air to use as a fertiliser in a greenhouse for photosynthesis and internal CO2 circulation. The CO2 can be captured directly from dry air, and released when the air is wet.
Project title Emergency Baby Incubator
Scholars Prof Albert Ko, Director of the Office of Service-Learning and the Lingnan Entrepreneurship Initiative (LEI)
Mr Adrian Lo Chun-kwong, Product Design Lead of the Office of Service-Learning
Description INCUVIA, a groundbreaking, modular, foldable, and affordable neonatal incubator is designed to save the lives of premature and underweight infants in underserved communities worldwide. It is portable, modular, easily monitored, transparent and foldable, and can be set up in minutes without tools. The low-cost, plug-and-play design is sustainable with reliable power - a 12V system using batteries and solar energy. INCUVIA has been successfully tested in the Philippines, and proved successful in field conditions.
Project title AI power-assisted wheelchair control system
Scholar Prof Albert Ko, Director of the Office of Service-Learning and the Lingnan Entrepreneurship Initiative (LEI)
Description CREW is a power-assisted wheelchair control system designed for caregivers, which brings the benefits of powered wheelchairs to users who cannot control them independently. Pressure-sensors in the handles of the wheelchair allow the caregiver easy control, and the wheelchair senses whether to move forward or apply the brakes intelligently without laborious effort, especially on a slope.
Project title AI Mosquito Diseases Control System
Scholar Prof Paulina Wong Pui-yun, Head and Associate Professor (Presidential Early Career Scholar) of the Science Unit
Description This Mosquito Risk Index uses the latest smart technologies, including IoTs, GIS, GeoAI, and Deep Learning algorithms, to geographically monitor, address, and anticipate mosquito-borne diseases in Hong Kong, and is the first system that can forecast mosquito occurrence up to three days in advance. The dashboard displays mosquito hotspots and alerts, and the goal is better disease management with community engagement.
Project title AI Road Risk Monitoring System
Scholar Prof Paulina Wong Pui-yun, Head and Associate Professor (Presidential Early Career Scholar) of the Science Unit
Description This real-time, accurate, all-in-one intelligent transport solution improves driving safety, facilitates fleet management, and improves road convenience and efficiency using autonomous driving technology and GeoAI techniques. It also develops a road hazard and traffic information geodatabase per road segment, allowing public transport drivers and fleet managers to receive immediate warnings and alerts of any hazards, and has a mobile app, dashboard, and dynamic mobility database, and GeoAI predictive capabilities.
Project title Smart Ageing home safety monitoring system
Scholar Dr Chloe Siu Pui-yee, Senior Lecturer of the School of Graduate Studies
Description H-Air is an intelligent home environment monitoring system that integrates electronic nose technology, thermal imaging, and AI-driven big data analysis. It provides effective protection through immediate detection, intelligent early warning, and coordinated response to multidimensional risks, including flammable gas leaks, indoor air quality, and elderly safety, and addresses a critical market gap by providing integrated, preventive, and responsive monitoring systems, thereby enhancing both safety and health management in residential settings. Its core purpose is to offer families and elderly care institutions a unified platform for environmental protection and health care.
Prof Sun Dong, Secretary for Innovation, Technology and Industry (middle), visits Lingnan's booth to learn about the AI-based Fencing Training and Assessment System, a project introduced by Prof Sam Kwong Tak-wu (left).
Visitors take part in the AI-based Fencing Training and Assessment System.
Prof Paulina Wong Pui-yun (middle) shows the AI Mosquito Diseases Control System, displaying various species of mosquitoes recently captured in Hong Kong.
Lingnan University highlights eight innovative research "Smart Healthy City" projects integrating AI and interdisciplinary research.
Lingnan University highlights innovative research projects
