The need
To be effective, a battery needs to have a sufficient cycle life at a temperature range between -20 and 60°C. For lithium-ion batteries, the lithium-ion cell works on ion movement between the cathode and anode electrodes.
Echion Technologies Ltd, a battery technology spinout company from the University of Cambridge, use their innovative anode materials to deliver an exceptionally long battery cycle life, superfast charging capability, and outstanding safety. This leads to unique performance and efficiency which enables users to sustainably electrify heavy duty transport and industrial equipment. Echion has developed a range of patented anode materials based on mixed niobium oxide for application in fast-charging lithium-ion batteries, where they achieve an excellent cycle at 25°C, with the ability to perform thousands of cycles over the battery lifetime.
Such mechanisms should work forever, but it has been observed that storage at an elevated temperature has the potential to decrease battery performance over time.
The solution
Funded by an Innovate UK A4I grant, Echion approached the National Physical Laboratory (NPL), to harness their secondary-ion mass spectrometry (SIMS) capability to help characterise the surface composition of lithium-ion electrodes. As part of the project, Echion also collaborated with the Science and Technology Facilities Council’s ISIS centre to use neutron diffraction at the Polaris instrument to study the bulk structure by investigating crystallographic changes taking place within the electrode.
Neutron diffraction was used to provide insight into the exact ageing mechanism of cell fading at high temperatures after cycling. Pre-prepared aged cells were examined at different temperatures and analysis was conducted to understand aging mechanisms by comparing the electrodes before and after cycling.
Neutron diffraction indicated no change in the bulk structure of the electrodes, proving that the structure itself remained stable. NPL’s SIMS capability found elemental differences in the electrode’s surface composition, indicating that cycle life issues are linked to overall cell design and surface effects, rather than the bulk of the mixed niobium oxide electrode.
The impact
The results of this research allow Echion to focus their efforts on solving cell design and surface composition issues and will accelerate the adoption and commercialisation of Echion’s next-generation ultra high-power, fast-charging cell material systems. Longer life cycles will be a key benefit to industrial users from manufacturers of buses, trains and ferries, to mining and farming, implementing environmental and public health improvements in reducing harmful gases and particulate matter, in line with the UK’s 2050 net-zero goal.