LeydenJar Technologies BV is a Dutch high tech venture and spin off company from applied research institute TNO. It is applying a solar cell production technology to produce a pure silicon anode for use in Lithium-Ion battery cells. The current generation of Li-ion battery cells does not have a sufficient energy density (the amount of energy stored per liter or kg of battery cell) for a wide range of applications, from consumer electronics to electric vehicles, from e-flight to renewable energy storage. In all these applications an increased energy density could lead to substantial customer value, such as a longer range for electric vehicles, more powerful applications for a smart phone, and smaller battery cells for small products. It could even enable new industries such as e-flight.
The current generation of Li-ion battery cells is based on graphite anodes. The maximum theoretical capacity of graphite to contain Lithium ions has been reached. An alternative material is silicon, as it can theoretically contain 10 times as much Lithium ions. However, silicon swells when Lithium ions enter it, up to 300%. In a normal case a pure silicon anode would crack after charging it, as an alloy is created, which expands, and the active anode layer is broken. This is why the battery industry is developing silicon particles that can withstand the swelling, and that can be used in the traditional production process of anode roll manufacturing. State of the art cells now have a maximum of 5% silicon in the graphite anode, increasing the energy density incrementally.
LeydenJar in stead has created a pure silicon anode that remains mechanically stable when it is used as battery material. This is because we create a porous silicon anode. We produce the anode in a single thin film process step (PECVD) in which silicon is grown in a columnar structure. The space between the pillars and inside the pillars allow the silicon to absorb the swelling and to remain intact. These pure silicon anodes can replace the traditional coated anodes in a Li-ion battery cell and can substantially improve the energy density, enabling battery cells with the highest energy density in the world.
The objective of this LEYDENJAR project is a) to engineer pure silicon anodes that can enable an energy density at stack level of 1.200 Wh/l (50% more energy density in an industry that can improve the energy density by 3% per year), b) to build a demonstration roll to roll production machine that can make pure silicon anode rolls, c) to validate this roll in a battery production plant.
This technology is strategically important for Europe. First because battery technology is an enabler for innovation in a range of industries. Second because the European industry needs to rely on the emerging European battery production infrastructure in order not to become too dependent on Asian suppliers. Thirdly because we can offer this production technology to European battery producers so that they can produce superior battery cells at similar cost and with reduced CO2 footprint.
