Impact of Li3BO3 Addition on Solid Electrode-Solid Electrolyte Interface in All-Solid-State Batteries.

Evgeniya Il’Ina,Boris Antonov,Alexander Pankratov,Svetlana Pershina

doi:10.3390/ma14227099

Abstract

All-solid-state lithium-ion batteries raise the issue of high resistance at the interface between solid electrolyte and electrode materials that needs to be addressed. The article investigates the effect of a low-melting Li3BO3 additive introduced into LiCoO2- and Li4Ti5O12-based composite electrodes on the interface resistance with a Li7La3Zr2O12 solid electrolyte. According to DSC analysis, interaction in the studied mixtures with Li3BO3 begins at 768 and 725 °C for LiCoO2 and Li4Ti5O12, respectively. The resistance of half-cells with different contents of Li3BO3 additive after heating at 700 and 720 °C was studied by impedance spectroscopy in the temperature range of 25–340 °C. It was established that the introduction of 5 wt% Li3BO3 into LiCoO2 and heat treatment at 720 °C led to the greatest decrease in the interface resistance from 260 to 40 Ω cm2 at 300 °C in comparison with pure LiCoO2. An SEM study demonstrated that the addition of the low-melting component to electrode mass gave better contact with ceramics. It was shown that an increase in the annealing temperature of unmodified cells with Li4Ti5O12 led to a decrease in the interface resistance. It was found that the interface resistance between composite anodes and solid electrolyte had lower values compared to Li4Ti5O12|Li7La3Zr2O12 half-cells. It was established that the resistance of cells with the Li4Ti5O12/Li3BO3 composite anode annealed at 720 °C decreased from 97.2 (x = 0) to 7.0 kΩ cm2 (x = 5 wt% Li3BO3) at 150 °C.

Highlights

All-solid-state batteries attract considerable scientific attention because such batteries have a number of advantages over commercially produced lithium-ion batteries, including increased safety, a wider operating temperature range, increased resistance to an aggressive atmosphere and high pressures, greater stability in the case of battery depressurization, and long lifetime [1,2,3,4]
2 wt% polyvinylidene fluoride (PVdF) binder and 3 wt% addition of PAN-based monomer into the anode material in order to increase the contact area between the Li7 La3 Zr2 O12 solid electrolyte and Li4 Ti5 O12 (LTO). We propose another method of solid electrolyte–electrode interface optimizing by the sintering process of powdered LTO with a low-melting additive
The stability of the cubic Li7 La3 Zr2 O12 doped by Al in contact with LiCoO2 was evaluated in our previous work [38]

Summary

Introduction

All-solid-state batteries attract considerable scientific attention because such batteries have a number of advantages over commercially produced lithium-ion batteries, including increased safety, a wider operating temperature range, increased resistance to an aggressive atmosphere and high pressures, greater stability in the case of battery depressurization, and long lifetime [1,2,3,4]. The cubic modification is of greatest interest as a solid electrolyte for power sources, since its lithium-ion conductivity at room temperature (10−3 –10−4 S cm−1 ) is 2–3 orders of magnitude higher compared to the tetragonal one [9,10]. The high resistance at the solid electrode–solid electrolyte interface is one of the critical issues that should be addressed for mass production of all-solid-state power sources [3,4,9,11,12,13]

Objectives

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Results

Conclusion