Critical Minerals, Critical Capacity and Critical Evaluation
Authors: Stephens Isabella 
Published: February 2024

The battery industry is placed at a critical intersection between the two most extractive and unsustainable industries: mining and energy, where current ‘business as usual’ will lead to catastrophic outcomes for society and life on earth. This gives it a unique opportunity to be an extremely effective disruptive technology, helping end colonial systems which rely on extraction and transfer of wealth and resources from the global south to the global north, and create fair and just energy systems. In order to do this, the battery industry must make batteries from ethically sourced materials, with long lifetimes, that are recyclable. A key question remains on how exactly to evaluate the true sustainability of the components of the electric future, particularly lithium-ion batteries (LIB).

This study presents electrochemical and materials characterisation data on several components of LIB, and a set of devised metrics for sustainability, to truly evaluate the potential of research cells in an industrial landscape.

Lithium-ion batteries challenge the current energy system, rather than a single use system that must extract, ship and burn fuels constantly, LIB present a potential cyclical system where batteries are recharged, then repurposed before finally being recycled. Metals must still be mined, but this can be achieved sustainably in conjunction with the communities that reside in those areas, as part of an ESG initiative. In developing new technology and with the vast expansion of new industry particularly across Europe, there is enormous potential and responsibility to put in systems to facilitate a just energy transition. This applies all the way down at a materials development level. The systems to evaluate this however, are few and not widely discussed.

In this work a case-study that aims to improve existing cell chemistry whilst focusing on its sustainability is presented. This includes the global context and in particular European criticality. The study builds on the premise behind the “Strategic materials Weighting And Value Evaluation" (SWAVE) framework to develop it further for new cell components and combinations.1

This study will focus primarily on the race to reduce cobalt and replace it with nickel and other transition metals. Reducing cobalt dependency is important to battery performance and ensuring that the energy transition is not reliant on a metal with restricted resourcing. However, whilst high nickel cathode content exhibits a higher specific capacity than cobalt-based material, it is less stable due to disordered Li+/Ni2+ cation mixing, lithium residuals upon the surface of the materials, and irreversible phase changes between the H2 and H3 phases at 4.2-4.3 V vs Li/Li+.2 Our results illustrate the difficulty in stabilizing the high nickel cathode materials with long lifetimes and discuss the possible successes in the results seen.

Our study also explores the possibility of expanding beyond single ion systems, using alternative anode and electrolyte materials containing different ion transport. One example is Sodium, which offers a cheaper and more sustainable alternative to Lithium, and so replacing any sodium in existing cells would reduce the cost of the cell and reduce the reliance on the critical material lithium. With the creation of metrics of sustainability as within this study, any loss of capacity can be evaluated in context of the sustainability analysis to give the true ‘value’ of a potential cell in the industrial context. The feasibility of these full cell configurations are discussed, with formation, capacity and life-time testing. These results show some promising cell capacities with a variety of cell chemistries and components, whilst keeping in mind the overarching aim of a just energy transition to evaluate the developments made.

References

1 R. Sommerville, P. Zhu, M. A. Rajaeifar, O. Heidrich, V. Goodship and E. Kendrick, Resour Conserv Recycl, 2021, 165, 105219.

2 H. Ronduda, M. Zybert, A. Szczęsna-Chrzan, T. Trzeciak, A. Ostrowski, D. Szymański, W. Wieczorek, W. Raróg-Pilecka and M. Marcinek, Nanomaterials, 2020, 10, 2018.