Time:2024.12.23Browse:0
The University of the West of England has produced a report on battery sustainability for the European Commission, which found that currently ubiquitous battery systems include raw materials that cause serious environmental and social problems. The report examines resource availability, toxicity, safety, production, and recycling and disposal impacts. The findings have been released against the backdrop of the EU's ambitions to create a bloc for battery manufacturing. In pursuit of global leadership in the technology, the EU wants to research alternative battery architectures with better ecological properties. The authors say that addressing electrode composition is a primary issue in achieving the goal of enhancing eco-politics. Regarding the issue of resource availability, the researchers concluded that while shortages will be an issue in the future - for some materials - this will not be an issue in the near or medium term. "Modest but foreseeable" growth in demand for lithium-ion batteries over the next decade, such as a 10% share of electric vehicles in the global car fleet, could still see significant supplies of lithium, manganese, nickel and natural graphite, the report found. The current issue report also states that 100% of the global fleet will have abundant electrification resources, even with cobalt, natural graphite, indium and other elements. However, supply may be affected by geopolitical risks, as the vast majority of required materials are mined in a handful of countries already struggling with geopolitical tensions. Electrolyte materials are also a cause for concern. According to researchers, the chemical breakdown of lithium-ion batteries results in the formation of highly toxic hydrogen fluoride. The electrolyte materials commonly used are also flammable, which could become a serious safety issue in the event of a car crash in a tunnel, for example. Alternative structures such as lead-acid batteries offer advantages in raw material mining. Most lead in circulation is recycled and can continue to be used. This eliminates the need for environmentally and socioeconomically unsustainable mining in tense geopolitical areas. Lead, on the other hand, is also highly toxic and is on the European Chemicals Agency’s candidate list of substances of very high concern. Additionally, the electrolyte used in lead-acid batteries - sulfuric acid - raises significant concerns for human health. Regarding energy density, the report states that lithium-ion batteries have a maximum ratio of 100-200 watt-hours per kilogram (Wh/kg). This is followed by sodium sulfur (120-150Wh/kg), sodium nickel chloride (95-120Wh/kg), lead acid (25-50Wh/kg) and redox flow (10-50Wh/kg). To avoid toxic effects, the authors propose a list of alternative compositions that can be utilized. They believe lithium-sulfur is one of the most promising candidates for the next generation of electric vehicles. This system avoids nickel and cobalt. The researchers say cathode materials containing sulfur, which is cheap and abundant, would make such batteries 22% less toxic, but currently they also have poor volumetric energy density - meaning they are light but large. Lithium-air uses oxygen as the electrode material and increases energy density tenfold. However, the report notes that in practice, the technology requires significant efforts to avoid degradation by pure oxygen in ambient air. This can be accomplished with air separation units and oxygen tanks, but these measures significantly reduce the energy density of the battery. The authors acknowledge that both technologies are also more energy intensive and therefore have higher greenhouse gas emissions. Finally, the researchers claim they "without a doubt" view sodium-ion batteries as the most attractive candidate to circumvent the adverse effects of lithium-ion systems. Sodium is very abundant and has nothing to do with geopolitical issues, they say. The batteries have lower energy density than lithium-ion batteries, but researchers believe significant progress is possible. In this regard, they also cite the European Strategic Energy Technology Battery Plan, which also highlights the potential of sodium ions. Designed for reuse The report also considers the issue of battery end-of-life handling. By 2020, approximately 25 billion lithium-ion batteries are expected to be used. In the EU and other markets, it is prohibited to bury or burn them due to their toxicity. Current efforts to recycle them are aimed at recovering nickel, cobalt and copper, the report's authors said. For economic reasons, other materials cannot be fully recycled even if it is technically feasible. For example, lithium often ends up in slag which is used as a building material. Additionally, there are concerns that reducing the use of cobalt in batteries would make lithium recycling uneconomical. The result could be that lithium is not recycled, negating the benefits of avoiding or using less cobalt. The second lifespan also plays a unique role, as EV batteries retain 75-80% of their initial capacity. This is enough to continue to be used for stationary energy storage. Although the researchers acknowledge that there is still something to be learned about the battery's performance and its longevity in its second life, pilot projects are underway and results will be available soon. The current process reverses the cathode and chemically decomposes the lithium. At the forefront of end-of-life processing are designs for recycling and reuse. The streamlined and simple structure of lead-acid car batteries has been an important factor in the high recyclability of this type of battery. Adopting such a design will make recycling of lithium-ion batteries easier and more cost-competitive. In addition to a unified structure, there should also be a "design for disassembly" aspect to separate materials as efficiently as possible. Quoting scientists Heelan et al.’s report adds: “Currently, we are looking at recovery and recycling as an afterthought. Closed-loop thinking and disassembly manufacturing should be considered from day one.”
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