Echion Technologies (Cambridge, UK) and iElectrolyte (Osaka, Japan) have demonstrated ultra-long cycle life Li-ion pouch cells. These cells combined Echion Technologies’ Mixed Niobium Oxide (XNO™) anode materials with iElectrolyte’s ionic liquid electrolytes which resulted in >98% capacity retention after 1000 cycles (1C/1C cycling). This is forecasted to provide at least >12,000 to standard cycle life limits of 80% of initial cell capacity. This paves the way to the sustainable electrification of high performance applications.
The prototype cells comprised of a high-Ni NMC811 cathode, XNO™ anode and iElectrolyte’s ionic liquid electrolyte. Each component was optimised to achieve a cell with high performance and excellent safety. In particular, the XNO™ material enables the avoidance of any SEI formation and has high specific capacity, and the ionic liquid electrolyte eliminates the flammability and volatility hazards associated within traditional organic electrolytes. The prototype pouch cells were then manufactured and tested at iElectrolyte.
Both the NMC811 and XNO™ electrodes were fabricated using an eco-friendly aqueous process. Figure 1 below shows >98 % capacity retention after 1000 charge-discharge cycles at 25°C from 0-100% State-of-Charge. High temperature cycling at 60°C was also conducted, with capacity retention being >83 % after 1000 charge-discharge cycles
Figure 1. Discharge capacity vs cycle number at 25 and 60 degC. The cells were cycled at 1C, CCCV to 0.1C charge/1C CC discharge between 1.3 – 3.0V.
All cells tested showed negligible gassing. This highlights a significant improvement over other chemistries that are known to gas during cycle life, such as LTO. These results show the > 1V vs. Li/Li+ redox potential of the XNO™ anode greatly minimizes electrolyte decomposition. Combined with the ultra-stable crystal structure of the XNO™ material, long-term and stable battery performance is achieved.
Following the outstanding initial performance of this cathode/anode/electrolyte trial, iElectrolyte and Echion are expanding their commercial relationship, with Echion supplying materials for the manufacture and commercialisation of 2 Ah pouch cells by iElectrolyte for high performance applications.
“Batteries with long cycle life are key to the economics of operation in industries driven by total cost of ownership and mission-critical performance requirements. This result is a great step towards the sustainable electrification of these applications”, says Dr. Loubna El Ouatani – Chief Product Officer, Echion Technologies
“Consisting of a high-capacity cathode, a stable ionic liquid electrolyte, and a high-performance anode, this cell is the most highly balanced system of reliability and performance in the LIB world. Not only that, but it can be manufactured in aqueous slurry systems with low environmental impact, which we have all been waiting for”, says Dr. Masashi Ishikawa – Chief Executive Officer, iElectrolyte