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As the world fights to make the shift from environmentally damaging fossil fuel energy sources to alternative, renewable, "clean" energy sources, lithium-ion batteries have begun to emerge as a significant source of energy supply.
Lithium-ion batteries fuel electric vehicles and make renewable energy storage possible. The last decade has not only seen a dramatic drop in the cost of lithium-ion battery production, but it has also seen researchers successfully enhance their energy capacity.
One significant advancement in lithium-ion batteries has involved the use of silicon to enhance storage capacity. Research has shown that in replacing the battery's graphitic anode with silicon, the battery's storage capacity increases ten times. As the world's energy demands increase, our ability to rely on fossil fuels diminishes, which means our use of lithium-ion batteries will likely play a vital role in the future of the energy sector. Therefore, innovations that increase their storage capacity will be invaluable.
However, silicon-based lithium-ion batteries are not without their problems. Their widespread use was initially prevented due to their relatively weak durability. Through the process of charging and discharging, the silicon is forced into phases of expansion and contraction. After a short period, stresses and fractures compromise the material, resulting in battery failure after a limited number of cycles. For this reason, silicon-based lithium-ion batteries were not initially adopted at a large-scale.
Graphene Flagship: Expanding the Use of Graphene in Clean Technology
Graphene Flagship, an EU-funded project that draws together the expertise of international teams of scientists, has helped to develop a way to overcome this limitation through the use of graphene materials. They innovated a method to stabilize the silicon-based lithium-ion batteries, enabling them to endure more than 300 cycles and enhancing their energy storage capacity by 30%, in comparison to alternatives.
The main aim of the Graphene Flagship project is to develop commercial applications of graphene by 2023. More than 145 academic as well as industrial partners are involved in the European Commission-funded work that primarily explores how graphene and graphene materials can be developed to solve some of science's major problems.
For this particular project, a team from cell manufacturer VARTA Micro Innovation GmbH, joined forces with researchers at the Instituto Italiano di Tecnologia (IIT), along with those at BeDimensional, a spin-off of IIT. The multidisciplinary, international research team pooled their knowledge and experience to provide a solution to the limited lifespan of silicon-based lithium-ion batteries.
Using Graphene to Overcome the Limitations of Silicon-Based Lithium-Ion Batteries
The team discovered that by adding a small amount of graphene to the batteries, the expansion was stabilized and the limitation of using silicon anodes is overcome. This is important because if a large amount of graphene had been required to achieve the same result, there would have been a reduction in the overall battery capacity.
Silicon in these batteries increases the overall amount of energy that can be stored within the cell, while the graphene prevents weakening and fracturing of the material.
The team created graphene-enabled coin cells with 30% greater storage capacities than similar solutions on the market. These cells are suitable for use in a wide range of small electronic devices, such as wristwatches, car keys, wireless headphones, and wearables.
The cells are set to revolutionize the market and can be adopted by a myriad of popular electronics.
Future Directions and the Environmental Cost of Lithium-Ion Batteries
There is a lot of promise for silicon-based lithium-ion batteries. Energy experts believe that lithium-ion batteries will play a significant role in the world's efforts to switch to clean energy in a bid to tackle emissions and prevent the detrimental impact of human activity on the planet.
Recent technological advances, such as electric vehicles and grid storage solutions, are well-positioned to take advantage of improvements in lithium-ion battery technology. In enhancing their capacity and overcoming the problems previously experienced by silicon-based technologies, the Graphene Flagship team's solution may be instrumental in enabling countries around the globe to better store surplus amounts of energy generated from renewable sources. This will not only help to support the widespread adoption of renewables but also facilitate the total switch from fossil fuels to clean energy.
However, currently, the environmental cost of lithium-ion batteries prevents them from being a completely "clean" energy source.
Around 80 to 90% of lithium is produced in Australia and South America. In particular, Argentina, Chile, and Bolivia form the "lithium triangle," where most of the continent's lithium production occurs. In this area, lithium production relies on brines, where salty water is administered to large areas of ground, creating pools just a few feet deep that evaporate over a few months. As it is moved from pool to pool, the lithium concentration in the brine increases until it can be separated and used in battery production.
The problem is that this process relies heavily on the availability of large volumes of water, which is a problem for the drought-ridden areas that are commonly involved in production. Many indigenous communities have voiced concern over the environmental impact of heavy water use in this process.
In addition, 2016 saw a high profile toxic chemical leak from a lithium mine on the Tibetan plateau. As a result of the leak, wildlife in the nearby Liqi river were harmed.
The processes involved in lithium mining will need to be addressed before the use of lithium batteries can reach their full potential as a renewable energy solution.
The work achieved by the Graphene Flagship project will undoubtedly cement the position of lithium-ion batteries in the future renewable energy market, particularly in the energy storage sector.
References and Further Reading
A pinch of graphene to increase batteries' lifetime and capacity. European Commission. https://ec.europa.eu/digital-single-market/en/news/pinch-graphene-increase-batteries-lifetime-and-capacity
Graphene enabled silicon-based lithium ion battery boosts capacity by 30%. Graphene Flagship. https://graphene-flagship.eu/news/press/Pages/Press.aspx#/pressreleases/graphene-enabled-silicon-based-lithium-ion-battery-boosts-capacity-by-30-percent-2979279
Lithium-Ion Battery Production Is Surging, but at What Cost? Green Tech Media. Emma Foehringer Merchant. https://www.greentechmedia.com/articles/read/lithium-ion-battery-production-is-surging-but-at-what-cost
The battery decade: How energy storage could revolutionize industries in the next 10 years. CNBC. Pippa Stevens. https://www.cnbc.com/2019/12/30/battery-developments-in-the-last-decade-created-a-seismic-shift-that-will-play-out-in-the-next-10-years.html
The spiralling environmental cost of our lithium battery addiction. Wired. Amit Katwala. https://www.wired.co.uk/article/lithium-batteries-environment-impact