1. What would you say are today the main strengths of Na-ion technologies compared to other emerging systems?

Na-ion technologies stand out mainly due to their raw material availability, sustainability, and safety. Sodium is an abundant and widely distributed resource, which reduces geopolitical risks and dependence on critical materials. In addition, Na-ion systems exhibit more stable thermal behaviour, improving operational safety, especially in stationary applications. All of this positions them as a very attractive solution for applications where cost, robustness, and sustainability are key factors.

2. What fundamental challenges remain to be solved in key materials such as layered oxides, hard carbons, and electrolytes for sodium?

There are still relevant challenges related to the structural stability of active materials, initial coulombic efficiency, and compatibility between electrodes and electrolytes. In the case of hard carbons, controlling the microstructure and sodium insertion mechanisms is critical. For cathodes, long-term stability and capacity retention remain priority areas. Addressing these issues is key to ensuring consistent performance and adequate lifetime at an industrial level.

3. What advantages does integrating design, processing, and validation bring compared to more fragmented developments?

Integrating design, processing, and validation allows technology optimisation from a realistic perspective, taking industrial constraints into account from the outset. This approach avoids developing materials that perform excellently in the lab but are difficult to manufacture at scale. It also accelerates learning, reduces unnecessary iterations, and generates industry-relevant data, facilitating technology transfer and reducing scaling risks.

4. What key learnings are you obtaining from validating aqueous and dry processing under pre-industrial conditions?

Validation of aqueous and dry processing is demonstrating that it is possible to significantly reduce environmental impact and manufacturing costs without compromising electrochemical performance. We are also learning which process parameters are critical to ensure reproducibility and quality at scale. These learnings are essential for Na-ion to be competitive not only technically, but also from an industrial and regulatory perspective.

5. To what extent do processing and scalability currently condition the design of Na-ion materials?

They decisively condition design. Today, new materials are not conceived without simultaneously evaluating their manufacturability, compatibility with existing production lines, and associated costs. The design of Na-ion materials must strike a balance between electrochemical performance and industrial viability, and this approach is increasingly integrated into research.

6. To what extent do processing and scalability currently condition the design of Na-ion materials?

They decisively condition design. Today, new materials are not conceived without simultaneously evaluating their manufacturability, compatibility with existing production lines, and associated costs. The design of Na-ion materials must strike a balance between electrochemical performance and industrial viability, and this approach is increasingly integrated into research.

7. What technical milestones do you consider most relevant in the transition from laboratory to prototypes up to 0.5 Ah?

One of the most relevant milestones has been demonstrating consistency and stability in larger-format cells while maintaining good performance and cyclability. Validation of materials and processes in near-industrial configurations has also been key, as well as obtaining reliable data on ageing and safety. These steps are essential to build confidence among potential industrial partners.

8. What metrics are currently critical for industry to trust Na-ion as a real alternative?

Key metrics include initial coulombic efficiency (ICE), capacity retention, long-term stability (SOH), and operational safety. In addition, cost per cycle and life cycle analysis are becoming increasingly important, as industry evaluates the technology from a global perspective, not only in terms of energy density.

9. In which application range do you believe Na-ion will reach commercial maturity first?

Na-ion will reach commercial maturity first in stationary applications, such as grid storage, renewable integration, or backup energy systems. In these cases, energy density is not the determining factor, and cost, safety, and sustainability are prioritised—areas where Na-ion offers clear advantages.

10. What role do LCA and LCC analyses play in technological decision-making?

Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) analyses are essential tools to guide technological development. They allow objective comparison of alternatives, identification of environmental and economic impact hotspots, and prioritisation of solutions with real market potential. In the case of Na-ion, they reinforce its value as a sustainable and competitive long-term technology.

11. Looking ahead 5–10 years, what advances will mark a turning point for Na-ion?

The turning point will come with large-scale demonstration of reliability, cost reduction, and process standardisation. Advances in more stable materials, improvements in processing, and the emergence of the first Na-ion gigafactories will be clear signals of maturity. From there, adoption could accelerate significantly.

12. How is CIC energiGUNE working to drive high-value Na-ion solutions and accelerate their transition from lab to market?

At CIC energiGUNE, Na-ion is being advanced through an integrated approach combining materials research, pre-industrial validation, sustainability analysis, and close collaboration with industry. The goal is to reduce technological risks, generate applicable knowledge, and position Na-ion as a real solution for sustainable energy storage, contributing to new industrial value chains in Europe.