Saphion Technology®
Commercially introduced in 2002, Saphion® technology refers to the processes and materials used in developing our novel lithium phosphate materials. This technology is incorporated into the cells that power our range of energy storage modules.
Fundamental properties of lithium phosphate, the core of Valence’s Saphion® technology, make for an intrinsically safe cathode material for lithium ion applications currently available. Because this material has a high resistance to the liberation of oxygen, no significant exothermic event occurs upon heating.
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The redox voltage is low enough that no electrolyte decomposition occurs, thereby affording long cell life. In a fully charged cell, no lithium is left in the cathode (unlike LiCoO2 where 50% still remains), thereby maximizing use of available lithium.
The graphic to the right depicts the olivine structure of one of Valence's lithium phosphate materials. The view is looking along an axis of the crystal structure. The polyhedra aid the eye in seeing the ions grouped as (green) Fe/Mg-enclosing octahedra and (yellow) phosphate tetrahedra.
Carbothermal Reduction (CTR)
Valence Cathode Materials are prepared using a unique and versatile preparative method called Carbothermal Reduction (CTR), a process to develop lithium phosphate cathode powder in a very efficient, cost effective, stable and scalable way.
Cheaper than conventional manufacturing methods, CTR makes Valence Lithium Phosphate powder longer-lasting, with more sustained conductivity, enhanced performance and ultimately leading to a better cathode material that is more easily manufactured into cells.
CTR is a process that enables Valence to efficiently convert Fe3+ into Fe2+ which can then be used in Valence Lithium Iron Magnesium Phosphate cathode powder. It uses carbon oxidation reactions to reduce iron oxides to a lower oxidation state. When carbon is used to reduce the iron oxide, a bond is formed between the remaining carbon and the iron. The stronger this bond, the greater the conductivity and overall performance of the cathode powder in any energy storage solution.
As lithium phosphate continues to grow in popularity as a safe chemistry, more and more companies, especially vehicle manufacturers, are becoming interested in switching away from sodium- and nickel- based batteries. CTR allows Valence to be very competitive in this market place.
A summary of CTR:
- Solid state method using carbon as a selective reducing agent
- Applicable to the preparation of a variety of electrode materials
- Allows the use of available and inexpensive raw materials, such as ferric oxide
- Easily scalable to production of active materials
- Better particle size control & material morphology
- Net result: optimal material performance produced in one single step