What Lies Beneath? Probing Buried Interfaces in Working Batteries

The interfaces between the different materials that make-up rechargeable batteries play a pivotal role in determining performance. This is where electrons and ions transfer between the electrodes and electrolyte during charging and discharging, as well as where many of the undesirable reactions that limit battery life take place. Understanding how the structure and chemistry of these interfaces changes during operation is critical to developing new higher capacity battery materials, fast charging protocols and models to predict when batteries need replacing. However, by their very nature, these interfaces are buried within the battery, making it extremely challenging to extract information without interference from the surrounding materials. This project looks at new approaches to investigate these interfaces.

Project presentation from the Faraday Institution Conference, November 2020

Objectives

The principal goal is to develop new in-situ and operando cells for probing buried interfaces in working batteries. These platforms will be portable across many different characterisation instruments and applicable to a broad range of battery architectures/chemistries, including liquid- and solid-electrolytes. The major research objectives are:

  • Develop and demonstrate an in-situ cell where each battery component can be removed, measured and the battery subsequently reassembled.
  • Develop and demonstrate an operando cell were the interfaces between components can be observed while the battery is charging/discharging.
  • Confirm that the electrochemical performance of these cells is representative: and
  • Demonstrate measurement across multiple characterisation tools (including hard X-ray photoelectron spectroscopy (HAXPES), secondary ion mass spectroscopy (SIMS), scanning electron microscopy (SEM), and X-ray diffraction (XRD).

Outcomes

Prototype versions of both the in situ and operando cells have been produced and undergone initial testing using solid electrolytes. These cells give good electrochemical performance while being compatible with the desired interface-sensitive methods.

Having tested protypes of the in situ and operando cells the team is now starting to perform targeted studies at national user facilities including Diamond Light Source and the Henry Royce Institute. The team is also extending the cell capabilities to operate with liquid electrolytes, which presents additional challenges when working in vacuum. Key battery materials problems have been identified for demonstrating the new capabilities offered and will be the focus of the next stage of the project.

In order to make the characterisation capabilities developed available to the wider research community in the near-term, the team is interacting closely with the degradation and solid-state battery projects in order to address questions relevant to these research programmes. Collaborations with industrial partners will help answer their materials problems. The potential for directly commercialising the in situ and operando approaches is also being explored with characterisation equipment manufacturers.

Project funding
£0.5m
1 July 2018- 31 March 2021
Principal Investigator
Professor Robert Weatherup
University of Oxford
University Partners
University of Oxford (Lead)
University of Manchester
Research Organisations, Facilities and Institutes
Diamond Light Source (STFC)
+ 3 Industry Partners

 

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