Ricerc@Sapienza

In the proposed research, functionalization of oxide-based solid electrolytes (SEs) by using ionic liquids (ILs) for all-solid-state lithium ion batteries (LIBs) is undertaken with the aim of reducing the interfacial resistances. SEs are promising materials which no doubt contribute to the improvements in the thermal stability and credibility of LIBs. However, oxide-based SEs generally have large grain boundary resistance and cannot exhibit a high ionic conductivity without high temperature sintering processes. As an alternative approach to reduce the grain boundary resistance, we propose the application of ILs on the SE surfaces so as to create amorphous interphases.

In the course of the last year, we have successfully obtained the composite electrolytes based on Li(7)La(3)Zr(2)O(12) (LLZO) and ILs. The ionic conductivity of pristine LLZO, specifically 2.0×10^-8 S/cm, was improved to 3.7×10^-4 S/cm merely by adding 15wt% of ILs. This result confirms the feasibility of our dual inorganic-organic concept. This year, our focus is placed on the improvement in interfacial properties between the composite electrolytes and electrodes. This is because the low conductivity across the electrolyte-electrode interphase severely limits the performance of the all-solid-state LIBs. Accordingly, the reduction of the interfacial resistance and the improvement in a long-term interfacial stability are the aim of this research, which will be done through the creation of high-performance solid electrolyte interphase (SEI) by suitably designed ILs.

The integration of inorganic-organic materials will improve the flexibility of inorganic SEs in terms of the multifariousness of ionic conductivity, the diversity of material design, and the variation in the structure of resulting batteries. We strongly deem that our composites will be a new class of electrolytes, which provide significant benefits for LIBs both in scientific- and industrial-level.