This symposium will focus on the fundamental and applied aspects of interface engineering and transport phenomena in next generation sustainable battery systems. As battery technologies evolve beyond lithium ion towards sodium ion, solid state and emerging chemistries, interfacial processes and mass transport increasingly govern performance, lifetime and safety. The symposium aims to bring together researchers working on electrode–electrolyte interfaces, charge and ion transport, and microstructure design to address key challenges in efficiency and durability. Contributions are invited on advanced characterisation techniques, operando studies, modelling of transport processes, and the design of materials and architectures that enable controlled local environments. Particular emphasis will be placed on sustainable materials, scalable processing, and strategies to enhance resource efficiency. The programme will provide a platform for discussing how interfacial and transport engineering can accelerate the development of practical, high performance and environmentally responsible battery technologies.