Energy storage is one of DECC's top priority areas for development, with the potential to massively cut the cost of decarbonising the electricity supply if a grid-scale electricity storage system to balance the variable output of renewables can be created. The challenge for residential energy storage (RES) systems is in providing safe, low-cost, long-life energy storage which can be coupled with renewable energy sources or 'economy' tariffs. This project proposes a scale-up of sodium-ion battery technology through industrial research. Sodium-ion batteries are analogous in many ways to the lithium-ion batteries that are in common use today; they are both rechargeable batteries. The use of cheaper and more abundant sodium in place of lithium addresses concerns of cost and sustainability of lithium ion technology as a residential energy storage solution. This project would innovate the scale-up of the cathode material manufacture from a few hundred grams to tens of kilograms, the surrounding sodium ion technology will be scaled up from single cells of a few Ah to 250Wh modules suitable for 4kWh residential energy storage at lower cost than current offerings. The project would include studies to understand the best design and operation of the cells and also the battery management system for both safety and longevity. This would be the first commercial residential energy storage sodium ion module and opens up the possibility of significant technology exploitation for all the commercial partners from intellectual property, materials manufacture, cell manufacture and battery assembly and distribution.