The Nanode™ is a three-dimensional, nano-structured, porous electrode that will overcome the limitations of today’s batteries by storing as much as 50% more energy than existing technologies. This allows the batteries to last longer between charges while also charging faster. These achievements are due to both the material structure and the use of tin as the active material. Tin is known to have much higher energy density than the current graphite technology, but until now its commercial success has been limited due to its tendency to swell during charging, causing stress in the electrode material and leading to a rapid loss in energy. Current commercial lithium ion batteries employ a foil/particle system as the electrode structure. The capability of such electrodes to deal with volume expansion of high energy materials is limited, because as the particles swell, the electrode expands.
The Tin Nanode’s™ integrated electrode structure contributes to the relaxation of stress associated with electrode materials undergoing high volume expansion. This is possible because thin films of active material are spread over a 3D and porous network of fibres, rather than stacking particles on a flat copper foil. This enables the electrode structure to deal with the volume expansion of the tin while retaining dimensional stability at the electrode level.
The major advantage of the Tin Nanode™ is its capacity to store the same amount of energy in a smaller volume, compared to commercial lithium ion batteries. This translates into a reduction in volume and cost of the overall battery.
In a cell assembly, a single Tin Nanode™ can replace both sides of a conventional graphite anode, as well as the current collector foil. This is done by tailoring the active material loading to match the capacity of two cathodes while maintaining the thickness of the Tin Nanode™. In this way, the Tin Nanode™ is able to provide an advantage in volumetric and gravimetric energy densities.
By integrating the current collector into the nanostructure, it is possible to eliminate the copper foil, the conductive additives and the binders needed for powder electrodes. In addition, the Tin Nanode™ may allow for easier wetting of the assembled cell for a number of reasons: the electrode is thinner, the obstruction of the current collector is removed and the liquid can flow freely through the porous structure of the Tin Nanode™.
Nano-Nouvelle’s manufacturing is based on high volume, low cost methods currently used in other industries. Using water-based (aqueous) processes imparts several key advantages, as the pressures and temperatures are kept within easy to manage ranges, and the resulting nanostructured material is achieved without any handling of nanoparticles. The resulting membranes can be handled similarly to existing metal foils in assembly processes for battery cells or other applications.