Most battery development so far responded to the needs of mobile applications. Such use cases require optimisation for energy density and power capability. Stationary storage prioritises different criteria: long life time and low cost. SOLSTICE has not only the ambition, but also the potential to meet this target. The novel Na-Zn cells will be designed custom-fit for the application as stationary storage. Thereby, SOLSTICE will produce sustainable batteries with responsible sourcing, optimal recyclability and a low carbon footprint in line with EU’s circular economy goals. Moreover, using widely available and low cost raw materials with sufficient resources and mining capacity inside the European Union will lower the market pressure on critical materials and make them available for other uses. The chemistry employed by SOLSTICE does not depend on any of the five otherwise essential battery raw materials (Li, Ni, Co, Mn, graphite). It will therefore help to improve Europe’s security of supply. The Na-Zn molten salt technology is undoubtedly one of the best options for stationary energy storage. It is the optimal choice of all molten-salt batteries, because it is eco-friendly and features economic active materials, which are non-toxic and abundant. All in all, the Na-Zn technology is excellently suited for stationary storage and its transfer to the market is realistic.


The overall objective of the SOLSTICE project is to develop a sustainable molten salt battery for use in large scale energy storage. The research is focusing on developing a battery with long lifetime using abundant, non-toxic and cheap materials. With the goal to provide low-cost large-scale electricity storage options for a de-carbonised future European energy system, SOLSTICE aims for the four main objectives itemised and detailed below:

  1. Optimise Na-Zn chemistries
  2. Develop and demonstrate robust Na-Zn batteries
  3. Assess Na-Zn based large-scale electricity storage
  4. Achieve sustainability and follow circular economy principles