January 2019

A major problem of current battery technology applying liquid, organic electrolytes is the formation of lithium dendrites. When they reach the cathode side, this results in a short circuit of the battery module. Leading to the module failure, up to the formation of toxic and combustible gases. Dendrites form due to nonuniform deposition of lithium on the anode side during battery charging. Liquid electrolytes and polymers cannot prevent dendrite formation within the electrolyte. Therefore, solid, inorganic and crystalline electrolytes have become focus of research, as they should not only have high conductivity, weight and volume savings (higher energy densities) and significantly lower temperature dependence of conductivity, but also sufficient density and a high shear modulus to effectively prevent the growth of dendrites.However, recent research in AG Janek has shown that it is still possible for lithium dendrites to grow through solid electrolytes, which are relevant for industrial applications. Critical factors for the formation or absence of dendrites are amongst others the temperature, the applied pressures, the applied current densities, and the preparation of the lithium metal foils (anode) used. The exact influences and critical parameters of these factors must be further investigated and the mechanism of dendritic formation in solid state batteries must be clarified and understood.In order to achieve an effective inhibition of dendrite formation, it is possible to synthesize novel solid electrolytes or to modify and protect the interface between anode and solid electrolyte with novel compounds. (Picture submitted by Simon Randau.)