51³Ô¹ÏÍø

AQUABATTERY, co-founded and led by Dr Jiajun Cen, has been awarded the prestigious European Sustainable Energy Innovation Award 2025.

The award, presented on 10 June in Brussels by the Vice‑President of the European Commission, recognises the sustainable infrastructure that underpins the research from .

AQUABATTERY’s innovative flow‑battery technology stores energy using only salt water, offering a scalable, safe and sustainable alternative to lithium‑based systems.

This breakthrough addresses Europe’s energy independence and grid reliability while reducing reliance on critical raw materials.

By using table salt and water...we can eliminate Europe's dependence on critical raw materials. Dr Jiajun Cen PhD alumnus, Department of Chemical Engineering and Founder of AQUABATTERY

Dr Jiajun Cen, who started building the company and developing the technology during his PhD at 51³Ô¹ÏÍø's Department of Chemical Engineering, accepted the award and said: “By using table salt and water - abundant and environmentally friendly materials - we can eliminate Europe’s dependence on critical raw materials and eliminate the fire, toxicity and explosion risks to people and habitats near battery sites.”

 was one of three finalists shortlisted for the  in the . The award recognises outstanding ongoing or recently completed EU-funded projects that show an original and innovative path towards the clean energy transition. 

This award celebrates their leadership in innovative energy storage, with huge potential to accelerate a resilient and climate‑safe energy transition across Europe.

AQUABATTERY also recently closed a €6 million seed round to support the deployment of its next-generation modular flow‑battery system and is preparing a fourth pilot installation in Delft, aiming for commercial readiness over the next few years. 

AQUABATTERY is a shining example of the mission-driven innovation we support at 51³Ô¹ÏÍø. Ben Mumby-Croft Director, 51³Ô¹ÏÍø Enterprise Lab

Commenting on the award, Ben Mumby-Croft, Director of 51³Ô¹ÏÍø Enterprise Lab, said: "It’s fantastic to see Dr Jiajun Cen and the team’s work recognised on the European stage with the EU Sustainable Energy Innovation Award. This is testament to the strength of 51³Ô¹ÏÍø's entrepreneurial eco-system and is a clear signal of the critical role startups like AQUABATTERY can play in advancing Europe’s strategic energy autonomy and accelerating the transition to renewables.”

AQUABATTERY is refining its product design with industry partners and scaling up its team to fast-track market launch and drive real-world impact.

ChemEng Enterprise-a rich history, an exciting present, a bright future

Commenting on the award, Professor Sandro Macchietto, Director of , said “We have been following and supporting the progress of Dr Cen and AQUABATTERY since its start. They gave a memorable presentation of their outstanding technology and business developments at our inaugural ChemEng Enterprise Day in May 2023; we are delighted to see them recognised by this top European Award."

This is the latest outcome of the highly successful decentralised Enterprise support programme launched by the Department of Chemical Engineering, unique within 51³Ô¹ÏÍø.

While AQUABATTERY itself did not draw directly on the programme’s pre-seed funding or mentoring support, the scheme has proven instrumental in empowering many other ventures.

It offers tailored startup advice, facilitates connections with 51³Ô¹ÏÍø stakeholders and funders, and culminates each year in the ChemEng Enterprise Day. This annual event brings together early-stage founders, investors, mentors, and alumni to spark collaboration from day one.

European Sustainable Awards

The  recognise outstanding individuals and projects for their innovation and efforts in energy efficiency and renewables. The nine finalists were selected by a  in three categories – ,  Action, and  – before being submitted to an online public vote. ​