Composite solid electrolyte, preparation method thereof and lithium storage battery

Abstract

The invention relates to a solid electrolyte, and discloses a composite solid electrolyte and a preparation method thereof, and a lithium storage battery. The composite solid electrolyte comprises a negative electrode side electrolyte layer, an ion dispersion layer and a positive electrode side electrolyte layer which are sequentially attached and compressed, the negative electrode side electrolyte layer is a PEO electrolyte membrane layer, the ion dispersion layer is Li3N, the positive electrode side electrolyte layer is a polymer solid electrolyte membrane layer, so that the lithium ion conductivity of the composite electrolyte is improved, the deposition uniformity of lithium ions in the charging process is improved, the lithium dendritic crystal forming rate is low, the cycle life of the lithium metal negative electrode is prolonged, and the cycle life of solid-state lithium storage is further prolonged; and the material still has a relatively high performance retention rate aftermultiple cycles.

Description

technical field [0001] The invention relates to a solid electrolyte, in particular to a composite solid electrolyte, a preparation method thereof and a lithium accumulator. Background technique [0002] As a chemical power source with high specific energy, lithium-ion battery is widely used in energy, transportation, communication, electric tools and other fields. Lithium-ion batteries have been commercialized since 1991 and have been used on a large scale. During this process, they have been accompanied by continuous development—from electrolytes with lower safety to solid electrolytes with higher safety today. The commonly used solid electrolytes are divided into polymer solid electrolytes (SPE) and inorganic solid electrolytes. [0003] Polymer solid electrolyte (SPE) is a kind of solid substance obtained by blending, plasticizing, and compounding inorganic substances with polymer as the matrix. At present, there are five types of polymerization based on polyethylene ox...

AI Technical Summary

Problems solved by technology

This new type of filler can not only improve the electrical conductivity of PEO but also increase its mechanical strength, however, the aggregation of nano-ceramic particles will lead to a decrease in lithium-ion conductivity

In addition, when the mechanical strength is increased, transition metal ions are introduced and some transition metal ions are transported in the amorphous region, resulting in Li + The transfer is uneven, the deposition of lithium metal is uneven, and the formation rate of lithium dendrites on the negative electrode is accelerated. Lithium dendrites are easy to puncture and detach from the solid electrolyte film to form "dead lithium", which reduces the cycle life and cycle performance of lithium batteries, and protects batteries from short circuits. The performance improvement is limited, and even under some other parameters, the short-circuit protection is even worse

[0006] Therefore, for PEO polymeric solid electrolytes, its high crystallinity leads to low ionic conductivity, poor mechanical properties and low withstand voltage, which limits its application and application effect.

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