Manufacturers’ Monthly sat down with Professor Neeraj Sharma from UNSW Science to discuss research into a sustainable lithium-ion battery component that utilises food-based acids.
Despite lithium-ion batteries having applications across most household battery energy storage, vehicles and electronics, the current technology has limitations due to its graphite anodes.
Graphite has a relatively low storage capacity, and when sourced and processed, it becomes expensive and detrimental to the environment.
In response to these limitations, professor Neeraj Sharma from UNSW is co-conducting the development of an electrode component that is more efficient, affordable, and sustainable.
The component utilises food-based acids found in foods like sherbet and winemaking.
“We’ve developed an electrode that can significantly increase the energy storage capability of lithium-ion batteries by replacing graphite with compounds derived from food acids,” said Sharma.
Urgent need for innovation
Sharma currently leads the Solid State and Materials Chemistry group, which works with government and industry to improve battery designs now and into the future.
“Our research ranges from synthesising new materials, characterising new and commonly used materials and devices, to recycling and end-of-life challenges,” said Sharma.
Sharma’s team is just one response to what is an urgent need for novel battery solutions, which has recently increased due to renewable energy infrastructure.
It was this demand for performance and sustainability improvement of battery solutions that led Sharma to explore the graphite anodes of lithium-ion batteries – commonly referred to as the negative side of a battery.
The graphite used in these anodes has a relatively low energy capacity and is associated with significant environmental impacts due to the sourcing, purification, and processing of the material.
“Graphite is not very environmentally friendly. It’s quite complex to mine and you have to use hydrofluoric acid and high temperatures to process it and get it to battery grade,” said Sharma.
“You lose anywhere from 30 to 60 per cent of what you mined to get battery-grade graphite.”
Given these challenges, Sharma’s team sought to address these issues by exploring alternative materials.
A sustainable alternative to graphite
To explore these alternative materials, Sharma began co-developing a groundbreaking battery component with PhD candidate, Matthew Teusner.
“We leveraged his expertise and his background and looked where we could go with that,” said Sharma.
“I just provided the foundational framework; all the credit should go to him.”
Teusner’s lab experimentation would reach a milestone when he reported inconsistencies in the reaction between food acid and the metal surface of a battery component.
“A metal plus an acid gives you salt and hydrogen. And it’s that salt that gives you excellent performance,” said Sharma.
Sharma said that this reaction resulted in a material that showed potential to improve upon the graphite anode’s performance and cost.
“We found that we can replace graphite with this material. It’s a food acid plus a transition metal – iron, zinc, manganese – it’s that reaction and the resulting product,” he said.
“Using food acids to produce water-soluble metal dicarboxylates presents a competitive alternative to graphite. We’ve demonstrated better battery performance, renewability and cost to better support battery demand.
“What’s nice about the energy storage density is that it is twice as much as graphite.”
The compound also showed improvements in sustainability. Where graphite is harmful to the environment in terms of sourcing, processing and manufacturing, the new material is not.
These findings were valuable in a battery manufacturing space that Sharma said is all about ways to move toward sustainability.
“How do we make batteries more sustainable? Everything from recycling all the way to processing materials itself and components,” he said.
This sustainability is initially seen in the sourcing of materials – the food acids that are utilised, as well as the tartaric and malic acids, which are easily sourced off the shelf as they are found typically in fruits, wine extracts, and even sherbet.
“At the moment, we’re buying the acids off the shelf from chemical manufacturers. We’re using quite pure feedstocks,” said Sharma.
One of Sharma’s next steps is to take this sustainability angle further and experiment with a potential future that could see food waste being utilised as a source of food acids.
“By using waste produced at scale for battery components, the industry can diversify their inputs while addressing both environmental and sustainability concerns,” said Sharma.
Food waste can be detrimental to the environment, contributing to three per cent of annual Australian greenhouse emissions according to the Department of Climate Change, Energy, the Environment and Water. This is a challenge that Sharma expects to address.
“We have to work out how to access these acids from food waste,” he said.
Alongside the sourcing of materials, the manufacturing processes are less environmentally intensive.
“They are processed with water instead of N-methyl-2-pyrrolidone (NMP), which is a toxic organic compound. The resulting performance using water-based processing is much higher than in NMP, which is fantastic. This is a benefit for sustainability by using a less environmentally intensive liquid,” said Sharma.
“We’ve got sustainable material, sustainable processing, which is a win, win scenario.”
After successfully identifying the sustainability advantages of this reaction, Sharma’s team saw the potential for a practical application.
This led to the development of a prototype electrode, designed to replace graphite anodes with the new compound.
The prototype, a single-layer pouch cell, is a smaller version of what could one day be used in a range of devices.
“Everything from your mobile phones, electric vehicles and power tools, to grid scale and household storage. We envision its design to be a drop in solution,” said Sharma.
Overcoming past and future challenges
Sharma said the process wasn’t without its challenges. Within the early stages of fabricating the electrodes, the two materials were refusing to form a uniform layer.
“One of the biggest challenges was when you fabricate these electrodes, you want a nice uniform layer. But what we were finding for a long time was that the material was just peeling off. Imagine you do some painting, and you leave out in the sun, what happens over time, it cracks and peels off,” he said.
“We worked for a long time, and then we figured it out. We adjusted the formulation, and we were able to make really smooth electrodes.”
Going forward, another challenge stems from the team’s current use of coin cells for experimentation.
“These are cells about the size of a small coin. The idea is to do as much testing as possible on them,” he said.
“We optimise and manipulate the loading of the material, and undertake performance evaluation for capacity, lifetime, and different charge discharge rates. We can do a lot of those tests in half cell format, and we can pull that up into a full cell within the same geometry – coin cells.”
Despite the testing freedom these coin cells provide, the team’s current challenge is exploring ways to upscale the technology to large pouch cell capability.
“We are working on how we can access the infrastructure so we can do that,” said Sharma.
He also foresees challenges in the scaling up and commercialisation of the technology, but insists that he is confident in the framework in place.
“Whether these materials make it commercially, well there’s a few steps there we would have to take. I would love to see it go from lab scale to commercial scale,” he said
“There could be issues in scale up, reformulation and in cell validation. However, I think we’ve got a good framework.”
Still new to the start-up game, Sharma said that a next step is the search for partners and investors to help take the technology from a prototype to a reality.
“This whole scale up idea is quite new to me. This is why I’m looking for partners. We’re looking for people who’ve done this sort of stuff before,” he said.
“We’ve got some interest from potential partners. Now we just have to see whether people are willing to invest.”
The team will also demonstrate industry viability and performance of the technology by running use/re-charge cycles at different temperatures and testing the technology’s applicability toward sodium-ion batteries, a cheaper, greener alternative to lithium-ion.
Collaborating now and into the future
Sharma said that collaboration on this technology is imperative in its development stage and moving forward.
“Matthew was the driver of this, and he’s amazing. We had a co-supervisor from the Australian Nuclear and Science Technology Organisation, Dr. Jitendra Mata, and we have used a whole bunch of different facilities at UNSW,” said Sharma.
“The business development managers have been fantastic. IP Lawyers also have answered all our questions. We’ve also worked with the folks at the Australian Synchrotron in Melbourne.”
In conclusion, Sharma expressed his satisfaction in what was, and is a team effort involving close collaboration with partners.
“It’s been quite an adventure,” he said.
As the demand for sustainable energy solutions grows, Sharma and his team are paving the way for a new generation of efficient and environmentally friendly batteries.
With the world shifting towards cleaner energy technologies, collaborations like these are set to be vital in driving change.