Sustainable Solid State Sodium Batteries

Introduction

The Li-ion battery, developed in the last 30 years, is a very successful technology. However, it now faces the challenge of powering the e-mobility revolution, requiring a large increase in raw resources availability. At this point in history, given the roadmap of the European Green Deal and the need to reduce CO2 emissions, such a scale-up should be seen as a unique opportunity to eliminate unsustainable elements from the batteries.

Challenges of Li-ion Batteries

The Li-ion battery relies on a series of elements that are critical, most importantly:

• Li
• Co
• Natural graphite

Moreover, the safety of Li-ion batteries is often in question, and their energy content still needs to increase to satisfy the demand for extended driving ranges.

Project Goals

In this context, 4SBATT aims to develop a solid-state battery based on Na, rather than Li, representing the best solution in terms of four key parameters:

1. Sustainability
2. Energy density (specific and volumetric)
3. Readiness of adoption (i.e., compatibility with existing Li-ion production lines)
4. Safety

Methodology

To achieve such a challenging goal, 4SBATT will operate at the cross-section between inorganic chemistry, materials science, and engineering. My team and I will develop a combined computational and experimental approach based on:

• Density functional theory
• In situ X-ray diffraction during synthesis

This approach will allow us to explore large amounts of temperature-dependent multicomponent phase diagrams for various classes of materials.

Development of Materials

We will design and prepare novel Na-based inorganic compounds for:

• Positive electrodes
• Solid electrolytes
• Negative electrodes

Then, the physical properties of materials and composite electrodes will be characterized to understand, improve, and engineer their performances.

Final Assembly

Finally, we will assemble solid-state batteries based on Na and sustainable elements such as Fe, Mn, and Si. These batteries will be intrinsically safe due to the non-flammable solid electrolyte, targeting record energy densities of:

• 300 Wh/kg
• 750 Wh/l at the cell level.