To properly ensure safe batteries, the development of safer and more environmentally-friendly ‘green’ electrolytes is urgently needed. The research aim of this project is to create performant single-ion conducting gel polymer electrolytes (SIC GPEs) from bio-sourced, abundant, reliable and low-cost materials such as cellulose, chitosan, agarose and alginate. This fellowship will address the electrolyte development from raw material to its application in a sodium-ion battery. The success of this proposal will be achieved by combining the knowledge and expertise of different laboratories. The synthesis and characterisation of the electrolyte will be realised at the Max Planck Institute of Colloids and Interfaces (MPIKG), Germany, where the fellow will be hosted under the supervision of Prof. Markus Antonietti. The advanced electrochemistry analysis will be carried out during the fellow’s secondments at Institute of Materials Science of Barcelona (ICMAB), Spain, with Prof. Rosa Palacín and Dr. Alexandre Ponrouch. The implications of practical realisation will be evaluated by Volvo Cars Corporation, Sweden, under the mentoring of Dr. Hanna Bryngelsson. The fellow will ensure the connection between the different laboratories’ expertise and will so also extend each partner’s research focus. During the 2-year project, the fellow and mentors will disseminate their results to both industry, academia and the general public through patents as well as articles in newspapers and scientific journals.