Deconstructing the Electrode-Electrolyte Interface by Novel NMR Methodology

Introduction

More efficient rechargeable batteries must be developed for utilizing sustainable energy sources and stopping the rapidly advancing climate change. The current technology cannot be merely extended for the next-generation storage systems. New approaches are required, especially for understanding and controlling the complex chemistry at the electrode-electrolyte interface.

Solid Electrolyte Interphase (SEI)

It has already been established that such control can, in principle, be realized by the solid electrolyte interphase (SEI), a stable passivating layer formed on the electrode. Such a layer should enable continuous transport of ions across it, but the fundamental understanding of what SEI components and architectures may give rise to such transport is not yet available.

Project Goals

The ultimate goal of this ERC project is to establish structure-function correlation for the SEI by implementing methodologies for:

1. Directly probing interfaces at the atomic-molecular level.
2. Guiding the design of novel interphases.

Methodology

We will achieve this goal by introducing to materials science a set of NMR 'tools' based on chemical exchange saturation transfer (CEST), commonly used to study dynamics in biomolecular-NMR. Here we propose to develop variants of CEST to probe ion dynamics across the SEI.

In Situ Implementation

Implementing these new approaches in situ, we will:

• Disentangle the multistep transport process at the electrolyte-SEI-electrode interfaces.
• Enhance sensitivity by Dynamic Nuclear Polarization from inherent polarization sources.

We will identify the SEI components participating in the ion exchange processes.

Integration with Battery Performance

Integrating our results with the battery performance, we will determine the pathways and bottlenecks for transport across the SEI.

Application of Advanced NMR Methods

Applying advanced NMR methods combined with controlled surface chemistry to state-of-the-art battery materials, such as:

• Lithium and beyond metal anodes
• High-energy cathodes
• Composite electrolytes

We will establish design rules for next-generation energy storage systems.