Forschungszentrum Jülich achieves success with fast-charging solid state batteries

As part of a funding programme of the China Scholarship Council (CSC), scientist Shicheng Yu at the German research institute Jülich Institute for Energy and Climate Research has developed the concept of a solid-state battery that permits currents during charging and discharging ten times higher than previously described in literature. This means that charging is possible in less than an hour, while up to now around ten hours have been considered necessary.
The improvement was achieved because all components consist of phosphate compounds that are chemically and mechanically very well matched. The liquid electrolyte of conventional lithium-ion batteries ensures very good contact between the electrodes. Such a gapless connection of two solids is not possible in principle, which is why the contact resistance between electrodes and electrolyte is significantly higher for solid state batteries. However, this type of battery offers considerable advantages in terms of the normally non-toxic and relatively inexpensive materials and, above all, because its low heat sensitivity makes it safe, reliable and durable.
The scientists led by Hermann Tempel have now developed an already patented combination of materials in which anode, cathode and electrolyte consist of different phosphate compounds. This allows charging rates of over 3C at a capacity of about 50 mAh/g. The phosphate electrodes are screen printed on both sides of the solid electrolyte. In initial tests, the battery cell still had 84 percent of its capacity after 500 charging and discharging cycles. Theoretically, a loss of less than one percent should be feasible, according to a statement by the Jülich Research Centre. The energy density can currently be 120 mAh/g and thus not too far below that of lithium-ion batteries.

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