Driving change: in pursuit of cobalt-free batteries
The increasing demand for electric vehicles has led to an increase in the demand for cobalt, which is used in Li-ion battery cathodes. However, concerns about the environment, ethics and the challenges inherent in cobalt production are motivating researchers to explore alternatives.
Head of the IfM’s Nanomanufacturing Group, Professor Michael de Volder, sheds light on the pioneering efforts to eliminate cobalt from electric vehicle batteries, offering a glimpse into a more sustainable era for electric mobility.
Embracing a multidisciplinary approach
Multidisciplinary research is proving to be a game changer in advancing electrochemical energy storage research. Professor Michael de Volder, who leads the IfM’s Nanomanufacturing Group, believes that this approach is paving the way for the creation of devices that can deliver quick and efficient electrical energy:
“When I started working on batteries about 10 years ago, they seemed to be a simple set of anodes and cathodes plunged in an electrolyte. However, I quickly realised that the battery schematics we learned at school are deceptively simple, and the operation of a modern battery is nothing short of a chemistry and engineering miracle. This explains why the invention of [the] Li-ion battery was awarded the Nobel Prize in 2019.”
The manufacture of batteries involves many complex operations. In particular, the manufacturing processes used for the battery electrodes have a more profound impact on the battery operation than previously assumed. Michael explains: “For instance, using the same active materials on the anode and cathode, changing the manufacturing process can influence how fast the battery can be charged or discharged and the overall energy and power density of the battery pack. More interestingly, manufacturing steps can also influence the lifetime of the battery and, therefore, its sustainability.
“However, modern batteries are such complicated ecosystems that optimising manufacturing by itself, without considering how this influences the chemical and physical processes taking place, is meaningless. This is exactly what makes batteries so exciting to study — they force you to understand disciplines that engineers don’t usually engage in much.”
Collaborating across departments in Cambridge and other UK universities, and fostering partnerships with industries and research centres, the group’s work addresses the intricate challenges of advancing battery technology. The same multidisciplinary ideology is reflected in Michael’s research group composition, which consists of engineers, material scientists, chemists and physicists.
Challenges of cobalt-free batteries
Lithium-ion (Li-ion) batteries are the dominant technology used in the manufacture of electrical vehicles (EVs) because of their high energy density and rechargeability. Therefore, research focused on battery technology plays a significant role in developing solutions to mitigate climate change.
A shift towards electric vehicles poses a significant challenge to the mining industry, particularly the mining of crucial battery elements such as cobalt, nickel and manganese. Cobalt, in particular, is a cause for concern because of the environmental and ethical issues associated with mining it, including unsafe working conditions, environmental pollution and the use of child labour. Although cobalt is necessary for enhancing battery stability and lifespan, its high cost and the associated issues have prompted researchers to investigate alternative cathode chemistries.
Researchers have developed new cathode chemistries that replace cobalt with nickel and manganese: “One such group of materials, which the automotive industry has increasingly adopted, are lithium nickel manganese cobalt oxides (NMCs),” says Michael. “Over time, various generations of NMCs have been developed with a decreasing amount of Co and an increasing amount of Ni content. In the most recent generations of these materials, up to 90% less Co is used in the cathode compared to the original LiCoO2 formulation that won the Nobel Prize.”
However, the shift to cobalt-free cathodes comes with a trade-off. While these cathodes are cost-effective and more eco-friendly, they can deteriorate more quickly than traditional counterparts posing new sustainability challenges.
“They tend to deteriorate faster than their traditional counterparts,” Michael explains. “Compared to formulations with higher Co content, these batteries experience quicker capacity fading, which means they need to be replaced more frequently, ultimately reducing their overall sustainability. This is a major concern, as the reduced lifespan of the batteries leads to their disposal in landfills, which ultimately undermines the environmental benefits of using cobalt-free cathodes.”
While the EV industry is gradually embracing cathodes with lower Co content, according to Michael, either the latest versions are not in use or their capacity is intentionally limited to slow down the degradation process because of stability concerns.
Balancing act: low cobalt cathodes
Given these challenges, the mission is to reduce cobalt content without compromising battery longevity. In the spirit of multidisciplinary research, the IfM Nanomanufacturing Group is working on a number of different projects with partners from around the UK.
The most significant project related to this research topic is a multi-university £22 million grant from the Faraday Institution, headed by Professor Clare Grey in the Department of Chemistry. Michael leads one of the three project work packages, working with colleagues from the University of Warwick, Imperial College London, Newcastle University, University College London, the University of Birmingham, the University of Oxford, the University of Sheffield and the University of Southampton. “We are looking at degradation processes that are a result of incompatibilities between classic electrolytes and new cathodes with very low cobalt content. The team is looking at developing better cathodes and the anodes of batteries,” he explains.
“As part of another grant, we are looking at how manufacturing processes affect the lifetime of these batteries. This work is sponsored by a £2 million ERC Consolidator Grant, on which I am the PI. This grant looks specifically at the development of scalable continuous processes for manufacturing better battery electrodes and bridging the so-called Valley of Death between academic research and industry. These new manufacturing processes impact not only battery lifetime but also their energy and power density,” explains Michael.
Finally, Michael’s group is part of a £14 million multi-university Faraday Institution grant headed by the University of Sheffield on the development of next-generation batteries that are entirely cobalt-free. The group is focused on the development and optimisation of manufacturing steps to suit these new material chemistries and to align their performance more closely with the requirements for their commercial adoption.
The group’s research findings will contribute to the manufacture of batteries to help mitigate climate change without creating new environmental challenges by relying on unsustainable materials.
Michael is optimistic that the landscape holds significant promise.
“The journey towards cobalt-free batteries aligns with the commitment to combat climate change and underscores the pivotal role of advanced manufacturing in shaping a cleaner and more energy-efficient landscape.”