Julian Kalhoff, battery business development manager at chemicals company Trinseo, argues manufacturers can overcome regulatory challenges by collaborating along the value chain.

While electric vehicles (EVs) will grow in significance as consumers transition from combustion-engine vehicles, legislation in the European Union could threaten EV battery production. Regulators are looking to eliminate solvent, and per- and poly-fluorinated substances (PFAS), some of which can negatively impact human health and the environment.

These bans would have significant implications as some PFAS materials are currently used in binder systems for cathode electrode manufacturing for lithium-ion batteries. To manage these potential threats, manufacturers should innovate existing binder technologies, which are critical to enabling essential battery functions, while also investing in new materials to meet sustainability requirements.

Introducing silicon

While lithium-ion batteries with graphite anodes have improved performance for years, the technology may be approaching its limits in energy density. Adding silicon as an active anode material may increase energy density – adding mileage and fast-charging potential to EVs. Pacific Northwest National Library has stated that silicon has the theoretical potential to provide 10 times the capacity of the same amount of graphite, resulting in EVs that can drive longer and potentially become more affordable.

Making up 27.7% of the Earth’s crust by mass, silicon is the second most abundant material on the planet and is easily accessible. Manufacturers can maintain a strong supply of silicon, thereby helping to improve the accessibility of high-energy battery technology. Silicon can also be obtained through more sustainable efforts, as sand and gravel mining usually has a limited environmental impact, according to the US Geological Survey.

Graphite production, on the other hand, relies on fossil fuels, causing synthetic production to be highly energy intensive, according to S&P. Mining graphite also has environmental consequences as the purification process typically uses hydrofluoric acid and sodium hydroxide – potentially hazardous chemicals that could be introduced into surrounding ecosystems. Moreover, the limited global natural supply of graphite might become subject to geopolitical arguments.

However, adding silicon to the anode creates more demanding binder requirements. Depending on particle structure, silicon is subject to a volume expansion of up to 400% upon battery charging. This mechanical stress can lead to particle cracking and electrode delamination, resulting in performance decay and hindering the addition of large amounts of silicon to the battery.

Today, up to 10% of silicon-based material can be added to current graphite anodes with commercially available binders, with the potential to develop new solutions that enable an increased amount. Manufacturers should invest in water-based binders compatible with silicon anodes to improve battery performance and their environmental impact.

Considering sodium-ion

Compared to lithium-ion battery technology, sodium-ion batteries are considered a more sustainable and advanced energy storage alternative, potentially reducing the total cost of EV ownership.

Although they offer slightly lower energy densities than their lithium-ion counterparts, sodium-ion chemistries utilise non-critical and low-cost materials. Sodium itself is one the most abundant earth crust elements and is predicted to lead to affordable mass-market batteries. In fact, BloombergNEF estimates that sodium-ion batteries could alleviate battery-market pressures and reduce costs as soon as 2026.

Depending on material selection, sodium-ion batteries can also provide fast-charging and long-cycle life features, making them an ideal technology for stationary energy storage applications. Moreover, water-based binder systems for both the anode and cathode electrode coating process can enable more sustainable and cost-efficient manufacturing processes compared to lithium-ion batteries.

Upcoming chemical regulations might threaten the battery industry, but manufacturers can overcome challenges by collaborating along the value chain. Water-based binder systems can support manufacturers by enabling new active materials and manufacturing processes, helping push the limits of performance while improving the capabilities and accessibility of battery applications.