How XNO? makes manufacturing anodes easy

Manufacturing electrodes is a complex process in which each stage needs to be meticulously controlled to achieve a microstructure that delivers maximum performance. If not done right, electrodes can experience cracks, delamination and uneven current distribution, ultimately reducing the capacity, efficiency and life of a battery.

So how does Echion’s XNO? compare to more conventional anode materials such as LTO and graphite when it comes to manufacturability?

How electrodes are manufactured

Electrodes are made up of three main components: an active material, a binder and carbon additives. The first stage of manufacture requires mixing these components together with an NMP (N-Methyl-2-pyrrolidone) or aqueous solvent to form a slurry. This slurry is then degassed to remove any air bubbles which could otherwise lead to defects in the surface finish of the electrode.

The slurry is then coated onto the substrate, or current collector, in a precise thickness via doctor blade coating or slot die coating techniques. Once coated, the electrode passes through a series of temperature-controlled drying ovens which evaporate the solvent and dry the electrode in a consistent manner, preventing the development of cracks or binder decomposition.

Finally, the electrode is compressed through pressure rollers. This process is known as calendaring and increases the electrode's density, reduces its porosity and enhances the contact between the particles within its microstructure.

XNO? is easy to mix

One of the biggest challenges of this manufacturing process is achieving a homogenous slurry mixture. ‘If the components within the slurry are not uniformly dispersed then this will lead to an inconsistent coating and poor electrode performance,’ explains Katarina Lukic, Cell Engineer at Echion. ‘Conventional anode materials such as LTO and graphite are typically very difficult to mix because they consist of nano-sized particles. Their relatively high surface area increases slurry viscosity and causes these particles to clump together; making it challenging to maintain uniform dispersion.’

‘The first thing our customers feedback when they use XNO?, is just how easy it is to mix,’ continues Lukic. ‘That’s because XNO? particles are micro-size, and so have a much lower surface area and don’t agglomerate.’

XNO? is easy to calendar

Another benefit of XNO?’s micro-size particles is that they can be calendared to a much higher density. This allows more coating to be applied for the same thickness, helping XNO? anodes achieve 1.5 times the volumetric energy density of LTO anodes.

‘The maximum calendar density you can get with LTO is around 2.0 g/cm3, but XNO? can be easily calendared to 3.2 g/cm3,’ highlights Lukic. ‘This is predominantly due to the nano size of LTO particles which simply can’t be compressed as much as XNO? particles. Whereas the micro-size nature, along with the high crystal density of XNO? makes it similar to a cathode material and can therefore be compressed during calendaring much more.’

‘Reducing this porosity is key to maximising contact between the particles within the anode’s structure and ultimately conductivity, leading to a much higher performing anode,' concludes Lukic.

So, not only is XNO? far easier to process than alternatives such as LTO and graphite, but it produces higher-performing anodes too, boosting the capacity, life and efficiency of lithium-ion battery packs.

What do you think is the biggest challenge when manufacturing electrodes?