High-performance anodes produced with a scalable and sustainable process

The superior properties of silicon

Current standard lithium-ion batteries (LIBs) feature anodes that mainly consist of graphite. However, the inherent maximum energy density that can be achieved with this material has been reached and significant improvements can therefore not be accomplished by any further graphite-related optimization. 

Thus, a major boost of the battery energy density requires the replacement of graphite with a superior material. Silicon, among all eligible elements, has the highest Li-ion storage capacity of around 3500 mAh/g, which is 10-fold higher than graphite. In addition, while Si is abundant everywhere (as an oxide), natural graphite has been identified by the EU as a critical raw material to be replaced. Its extraordinarily high capacity makes Si a strategic material for future LIB cells, to enable higher power cells through reduction in electrode thickness, extend EV range by increasing LIB energy density by 50%, and match emerging conversion cathodes. 

The full potential of silicon, however, can only be exploited if it is integrated in the form of nanostructured pillars or particles. The latter withstand extreme volume changes during the uptake of lithium and, thus, do not lead to battery deterioration as in contrast to bulk silicon.

Floatech's unique process of nanostructured silicon anodes

Floatech has developed a cost-effective and scalable process to produce free-standing silicon nanowire (SiNW) sheets. These can be easily integrated into LIBs as high capacity anodes and withstand extreme volume changes during lithium uptake.

Floatech’s process has emerged from a new branch of chemical vapour deposition (CVD) research that utilizes floating catalyst nanoparticles for enhancing traditional CVD processes. In this, a gaseous Si source is directly converted into a free-standing SiNW sheet, a semi-finished electrode, in one single process. In addition, because of the ultra-long length of the constituent nanowires, the semi-finished electrodes are mechanically robust and do not require reinforcing binders. Hence, costly dispersions of raw materials and the use of substrates are eliminated. Our SiNW sheets can be directly deposited on current collector foil for integration into LIBs as full anodes.