Performance-limiting electrochemical reactions in lithium-based batteries

Figure 1. Two-dimensional lithium deposition on a lithium electrode.

Background

Despite the very frequent use of lithium-based batteries there are still a number of unanswered electrochemical questions that need to be addressed in conjunction with these batteries. These questions generally relate to the loss of performance seen for the batteries during their cycling. These questions hence relate to the energy and power densities as well as the lifetime of the batteries, all of which are essential with respects to most applications (such as electric vehicles and large-scale electric energy storage) involving lithium-based batteries.

Our research is focused on the development of a significantly improved electrochemical understanding of the performance-limiting effects to enable the development of lithium-based batteries with significantly improved performances. Our recent results, which are based on detailed electrochemical investigations, clearly show that these effects cannot be fully explained by contemporary models and that additional phenomenahence must be taken into account. More importantly, the results indicate that it is possible to extend the lifetime of the batteries significantly and that it may even be possible to regenerate failed batteries. The scientific and practicalimplications of our findings are therefore considerable.

The figure above, which illustrates the result of two-dimensional lithium deposition on a lithium electrode, demonstratesthat it is indeed possible to solve the well-known lithium-dendrite and mossy lithium problem. This image was a winner of the 2018 Materials Today competition.

Aims

Our main goal is the development of a significantly improved electrochemical understanding of the performance-limiting effects in lithium-based batteries to enable the realization of lithium-based batteries with significantly improved performances.

Approaches

In our research we address a number of previously unaddressed electrochemical questions regarding lithium-based batteries based on careful analyses of electrochemical data using electrochemical techniques that rarely are employed within the lithium-based battery field. We currently mainly focus on the capacity losses generally seen for e.g. lithium-alloy forming electrode materials such as silicon, tin and aluminum as well as the attainment of two-dimensional deposition of lithium on lithium electrodes.

Keywords

Lithium-based batteries, electrochemistry, capacity loss mechanisms, lithium-trapping, dendrite formation, electrodeposition, nucleation.

Links

Link to the webpage ”Electrochemistry and corrosion” at Uppsala University

Project leader

Leif Nyholm

Other project members

David Rehnlund
Ruijun Pan
Zhaohui Wang
Charlotte Ihrfors
Yu-Kai Huang

Additional Funding (apart from STandUp for Energy)

The Swedish Research Council (VR), The Swedish Energy Agency.