Understanding the surfaces of fast charging battery materials: SURF-FAST

At Nyobolt, we are working on creating an ultra-fast charging lithium-ion battery that can be used in both electric vehicles and consumer goods applications, minimizing downtime by shortening the recharging period, and reframing customer's expectations about where and how we can use batteries.

Developed at the University of Cambridge, Nyobolt's ultra-fast charging technology uses niobium tungsten oxides (NWO) as battery anode materials. Conventional lithium-ion materials typically contain graphite or lithium titanate (LTO) as anodes and suffer from both safety and performance issues, the latter due in part to their inherently slow lithium ion movement throughout the material. In contrast, NWOs enable lithium ions to move rapidly though their structures - with ion diffusion coefficients that are several orders of magnitude higher than those in e.g., LTO. This is the key to their ability to be used for a quicker charge and higher power in a battery. What's more, these high ion mobilities can be achieved without nanosizing. This has a significant impact on sustainability - we can avoid the complexity and cost of nanoparticles without compromising on the performance. Prof. Clare Grey and Dr Sai Shivareddy founded Nyobolt Limited in 2019 to bring this UK IP to market and offer a fast-charging solution to customers.

In a battery cell, these anodes (which are themselves a composite material) will be paired with a typical cathode electrode and combined with a separator soaked in an electrolyte solution. The interaction of all these components and the resulting changes to the various surfaces present can have a significant impact on the performance of the battery during its operation. Small changes in the chemistry and cycling conditions can have a big influence on key performance indicators, such as lifetime, rate-performance, and capacity retention. These will also impact the overall safety of the cell.

This project seeks to study these changes to the surface using techniques at the National Physical Laboratory which provide both sufficient sensitivity and complementary information (e.g. SIMS, Raman, XPS), which are not currently readily available in routine R&D work programs at Nyobolt.

By understanding the surface, we can tailor solutions by changing the battery chemistry or electrochemical conditions during cycling to target improved performance, creating a better product to out-compete current state-of-the-art technology. A better fast-charging battery can enable the wider and faster adoption of electric vehicles in UK and electrification more generally and contribute to the UK's net-zero strategy.