How to crack lithium penetration? Improve the smoothness of solid electrolyte of lithium battery as the key

SMD aluminum electrolytic capacitor

According to foreign media reports, researchers at the Massachusetts Institute of Technology (MIT) and their German counterparts have suggested that the use of a solid electrolyte with a smooth surface prevents harmful lithium infiltration and enhances The performance of solid state lithium ion batteries.

Researchers have tried to solve such problems by adding ceramics and other materials to the solid electrolyte. Although solid electrolytes can solve the flammability problem of electrolytes, tests have shown that the properties of such materials are not stable and the frequency of short circuits is higher than expected.

According to new research, the problem is that previous researchers chose the wrong direction, and they aim to find a material that can make solid electrolytes. They believe that the firmness or shear modulus of the material will determine whether dendrites will penetrate the electrolyte. However, according to new analysis, the smoothness of the surface is the key to the problem. Fine cracks and scratches on the surface of the electrolyte will lead to the accumulation of metal.

After the electrochemical reaction occurs, lithium (ion) from the electrolyte will begin to accumulate on the surface of the fine ruthenium (including: fine pits, cracks, scratches). This situation will continue as lithium ions begin to accumulate at the enthalpy. Surprisingly, the accumulation begins at the tip of the dendrites rather than from the base, which in turn leads to the formation of solid buildup, as if a wedge was used to dig the crack wider.

This suggests that researchers need to focus their research on improving the smoothness of solid electrolyte surfaces, which may eliminate or greatly reduce the amount of solid-state electrolyte dendrites generated. To avoid flammable problems, solid lithium metal electrodes may be used in the future. In addition, this move may double the energy density of lithium-ion batteries.

The formation of dendrites will lead to short-circuit faults, which once became a technical problem for lithium batteries.