Lithium-ion batteries – what is all the fuss about?

Beatrice Browning, PhD researcher for the Faraday Institution writes for Air Quality News about the importance of accelerating our understanding of lithium-ion batteries. 

Worldwide, fossil fuels are used in abundance. However, the use of these non-renewable fuels is already having an adverse effect on the environment and devastating impacts on human health.

In 2017, the transport industry was responsible for 25% of the total greenhouse gas emissions in the EU.

Due to increased pressure to reduce these emissions, there is a universal demand for the electrification of road vehicles, and the government have finally put in place relevant legislation and strategic funding to prepare for this.

The ‘Industrial Strategy Challenge Fund’ (ISCF), is a major component of the government’s plan and is essential to ensure that research and development is done to advance the UK to the forefront of relevant science and business opportunities.

In 2017, £246m of this fund was invested into forming the Faraday Institution: an independent institute committed exclusively to battery research, with the intention of advancing the electrification of the transport industry and establishing the UK as one of the world leaders in battery technology.

What are lithium-ion batteries and why are we interested in them?

Generally, when told to think of batteries, we tend to think of common household batteries, found in our television remotes or kitchen weighing scales.

These single-use batteries, known as alkaline batteries, are generally composed of zinc and manganese dioxide.

When considering mobile phones, laptops and other portable electronic devices, the batteries are predominantly lithium-ion batteries (LiBs). This has been the case since their commercialisation by Sony in the early 90s.

LiBs have a high energy density, stability, and are fast charging. They are also able to be recharged hundreds of times with a slow rate of capacity fade.

Why do we need LiB research for use in EVs?

Despite them being well-documented and understood, there are numerous issues which come into play when using LiBs in EVs.

Firstly, if EVs are to replace conventional petrol and diesel engines, it is vital that these vehicles are superior.

This means that the battery lifetime must be comparable to that of a ‘full tank’ of petrol, and the battery must charge up as quickly as a petrol tank would fill up at a service station.

Furthermore, the degradation of LiBs is an extremely complex science. Understanding how cells degrade is hugely important, as the final state of an EV battery will determine its recyclability/ reusability.

With regard to these issues, challenges of LiBs which need to be overcome can be grouped into the following:

1. Cost issues — the price of the materials which make up the battery needs to be reduced, to make the price of an EV reasonable
2. Energy/power density — the amount of energy the battery can store (and the power the battery has) needs to be increased to ensure it is comparable to petrol and diesel vehicle
3. Battery safety — the battery packs need to be as safe as physically possible
4. Battery lifetime — the lifetime of the battery needs to be reasonable, preferably the same as the lifetime of the vehicle itself
5. Operating temperatures — the performance of LiBs is affected by temperature, therefore a wider temperature range must be optimised
6. Predictability of battery behaviour — being able to predict how the battery will perform and how it will age will be extremely valuable to manufacturers.
7. Recyclability — LiBs are not currently routinely recycled, therefore putting in place efficient recycling practices and designing LiBs for recycling is essential to ensure the finite materials within the battery are not extensively depleted

These issues, alongside necessary legislation and infrastructure which needs to be put in place, emphasise just how vital lithium-ion battery research facilities are in bringing the UK to a place where a full-electric vehicle fleet is plausible.

At the Faraday Institution, there are researchers from an array of backgrounds, from chemistry, law, engineering, mathematics and computer science, who are committed to tackling these challenges, and it is essential that this research continues to progress for the UK to reach the carbon emissions targets by 2050.

Photo Credit – Pixabay