NANOCOMPOSITES BASED ON LITHIUM PERCHLORATE IN THE METAL-ORGANIC FRAMEWORK MATRIX

1 Artem Ulihin, 1,2,3 Nikolay Uvarov, 1,2 Valentina Ponomareva, 4Konstantin  Kovalenko, 4Vladimir Fedin

1 Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia

2 Novosibirsk State University, Novosibirsk, Russia

3 Novosibirsk State Technical University, Novosibirsk, Russia

4 Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russia

E-mail: ponomareva@solid.nsc.ru

Introduction

Solid electrolytes with high lithium-ion conductivity are important materials for solid state lithium batteries. Among the solid electrolytes composite systems are of special interest as their physical properties may be easily adapted to a particular application by variation of the type and concentration of the components. Metal-organic frameworks (MOFs) are excellent porous matrices for preparation of nanocomposites with unusual physical and chemical properties.

Results and Discussion

In the present work nanocomposite solid electrolytes LiClO4 – CrMIL101 were prepared and their electrical properties were investigated at the temperature range of 300-450 K. It was demonstrated that lithium perchlorate easily penetrates into the pores of MOF with formation of nanocomposites. Reproducible heating-cooling cycles of conductivity were observed in vacuum. The concentration dependence of the conductivity goes through the maximum and reaches ~10-3 S/cm at 430 K (Fig.1), the activation energy for conductivity changes from 0.93 eV for pure lithium perchlorate to 0.62 eV in the nanocomposites. The value of electrochemical decomposition was determined as 3 V at 500K. It suggests that the ionic conductivity is caused by lithium cations rather that protons or electrons. The results were interpreted in terms of the model of the composite in which the lithium salt uniformly covers surfaces of the MOFs pores. According to the model with the increase in the concentration of the MOF the thickness of the salt layer may decrease to a single layer level with the changing the salt properties due to size effect.

Figure 1. Concentration dependence of conductivity of the (1-x)LiClO4 - xCrMIL-101 composites.

The work is supported by the Russian Fund of Basic Research, grant No.18-29-04039.