Novel cell architectures for metal-air battery chemistries

The introduction of novel materials and improvements in the internal cell architecture have led to a gradual increase in the energy density of secondary Li-ion batteries. The pathway for further evolutionary improvements is expected to reach its limit by 2030 with gen. 4c batteries. New material systems and cell types (gen. 5 batteries) will continue to offer improved energy density beyond this point, reaching energy densities up to 2000 Wh/L.

Metal-air batteries are promising avenue towards exceptional energy densities, but face a multitude of technical challenges.  The metal–air technology is based on the controlled reaction of oxygen from the atmosphere (cathode) with a high-energy metal such as lithium, sodium, or zinc (anode), which delivers a remarkably high specific capacity (Ah). The development of rechargeable “breathing” batteries presents several challenges, which are mostly associated with parasitic reactions limiting the reversibility of the electrochemical process and the full utilization of the high theoretical capacity. Whilst fine tuning of the electrolyte formulation along with the use of additives, catalysts, and mediators may mitigate the side reactions in the cell, improved electrode nanostructures may boost both the achievable capacity and the current density, thereby enabling high-energy and high-power applications. Further, the reaction products between the metal and O₂ are often insulating and chemically irreversible. As such, modifications to both the cell architecture and chemistry are required to improve the cycle life, energy density, and power density of these battery types.

For this research topic, you will build on the decade long experience in the field of energy storage and conversion at imec, specifically on solid composite electrolyte development and nanostructured electrodes with extremely high surface area. A novel electrochemical test cell and methodology will be devised to control and monitor the redox reactions occurring during operation. The electrolyte will be engineered to tune and control the oxygen and cation diffusion and subsequently connected to a nanostructured gas diffusion electrode to minimize activation overpotential losses and facilitate O₂ flow to the electrode. By evaluating several performance metrics in laboratory-scale battery prototypes, you will gain insight into the critical aspects of materials engineering that will enable rechargeable metal–air batteries. You will be working in an interdisciplinary team of PhD students, researchers, and engineers, while collaborating with various universities, research institutes, and companies. Meticulous analysis of the cell will be conducted in the state-of-the-art facilities of imec, comprising both physico-chemical characterization of the reaction products, and monitoring of the downstream gas flow during battery cycling to evaluate the material interactions.