Reducing the Environmental Footprint of Batteries
As the world shifts towards renewable energy and electric vehicles, the demand for batteries is skyrocketing. However, this surge in battery usage comes with significant environmental concerns, from resource extraction to disposal issues. (read our article on "How green are batteries, really?")
In an effort to address the environmental challenges associated with conventional batteries , researchers and companies are working to develop greener battery technologies. These innovations may help reduce the environmental impact of batteries at each step of their life cycle.
a. Technologies to Improve Battery Mineral Extraction
Developing methods to extract raw materials from the earth with minimal environmental impact will be crucial for preventing further damage to our planet. This means implementing extraction techniques that use less water, less energy, and less harmful chemicals, as well as responsibly dealing with tailings and other waste streams and making efforts to minimize deforestation and ecosystem disruption.
With respect to lithium, a process referred to as direct lithium extraction, in which lithium ions are selectively removed from lithium brine using a solid absorbent, is being investigated as a more sustainable alternative to evaporation-based techniques featuring lower water consumption and carbon dioxide emissions. Another method being explored for obtaining "green lithium" is the use of geothermal brines — concentrated saline solutions that have naturally circulated through very hot rocks deep in the earth to become rich in lithium and other elements. Initial efforts to exploit these resources are now underway, with at least one pilot plant due to be constructed in Cornwall in the United Kingdom. Similar geothermal waters can be found in Germany and the United States, and lithium supplier Vulcan Energy recently reported its first production of lithium chloride from its extraction plant in southern Germany.
b. Newer Battery Chemical and Battery Designs Hold Promise for Lower Environmental Impact
Another way to reduce the environmental impact of batteries is focusing on intrinsically more sustainable battery designs and battery chemistries:
- Sodium-ion batteries: These batteries store energy using sodium ions rather than lithium ions, thus avoiding the need for lithium entirely. Sodium is a much more abundant element than lithium and can be readily obtained with less environmental impact (e.g., from seawater), while the long expected cycle life of sodium-ion batteries should reduce the frequency with which they need to be replaced.
- Solid-state batteries: The higher stability of these emerging batteries, which use a solid electrolyte rather than a liquid one, is expected to allow a longer lifespan, meaning that they need to be replaced less often. However, their production is currently more expensive and complex, necessitating further research and development.
- Lithium–sulfur batteries: By using metallic lithium rather than lithium ions and abundant sulfur rather than heavy metals, these batteries are expected to enable much higher energy densities — meaning smaller and lighter batteries — while avoiding some of the more environmentally damaging elements found in lithium-ion batteries.
- Cobalt-free batteries: Cobalt is one of the more problematic raw materials employed in battery manufacture, with much of the world's deposits found in politically unstable countries and mined under hazardous conditions with major ecological consequences. Research is underway to develop alternative battery chemistries that perform well without requiring cobalt, such as those based on lithium iron phosphate or organic compounds.
- Silicon anodes: Replacing the graphite anodes found in most lithium-ion batteries with silicon anodes holds promise for realizing higher capacities while avoiding the fossil fuels needed to manufacture or mine graphite.
- Flow batteries: In contrast to conventional batteries, flow batteries rely on pumping two liquids through the system on either side of a membrane. Although these tend to be bulkier and heavier than standard batteries, they have a longer lifespan and are more readily recyclable, making them attractive and durable options for stationary applications such as grid energy storage.
