In the area of lithium ion accumulators, the lithium iron phosphate system is very promising, especially as regards application in the automobile- and power plant industries. In an earlier DBU project, an innovative approach to increasing the ionic and electrical conductivity of the cathode material was developed. The powder properties were substantially improved by increasing conductivity and moisture sensitivity. In addition, on the anode side an equally innovative approach was developed towards the achievement of higher capacity.
Silicon technology already on the market was used as a basis and further built upon. As an anode material, silicon has the highest known energy density for the storage of lithium. Its disadvantage lies in the change in volume in the charging and discharging processes. These problems can be solved through the use of nanopowders. Their high impurity density leads to reduced volume effects, and improves the diffusion of the lithium. The further treatment of the nanopowders with physical and plasma-chemical separation technologies allows a wide range of options in material composites and structuring. An additional important developmental aspect was the improvement in corrosion resistance in the aluminum energy-collector foils, to which the electroactive silicon anode material is applied.
The transfer resistance factors can be minimized with a special plasma coating. The technical solutions developed in the DBU projects were integrated into the lithium accumulator production realized by the ecc Repenning GmbH company in 2012, primarily for stationary applications. These accumulators are characterized by outstanding cycle stability and high tolerance to peripheral charger tips.
