Degradation Prevention of Latp Towards Li Metal and Interface Improvement By Layer-By-Layer Polymer Assembly Technique

Abstract

Degradation of Li1.3Al0.3Ti1.7(PO4)3 (LATP), NASICON-types solid electrolyte (Figure 1) towards Li metal creates a dramatic issue, as materials itself is very promising due to its stability towards air and moisture and facile fabrication methods.Figure 1. Illustration of Li1.3Al0.3Ti1.7(PO4)3 degradation towards Li metalSolid electrolytes containing titanium, germanium suffer from reduction while contacting with Li metal. Reduction of Ti4+ to Ti3+ in LATP leads to a formation of mixed conductive interphase, a secondary phase that hinders lithium ion conduction between the solid electrolyte and electrode. In the majority cases, this problem can be solved by applying artificial interlayer that prevents the direct contact of these components. In addition, the protective interlayer also helps to reduce interfacial impedance that present between electrolyte and electrodes. In our research, we resolved it by applying thin composite gel polymer electrolyte (GPE) as interlayer using layer by layer (LbL) technique. Despite preventing the side reaction, the simultaneous coating on both sides of LATP pellets improved interfacial contact between cathode and electrolyte, anode and electrolyte. The effect of this modification was characterized by physical, chemical and electrochemical analyses. Acknowledgement This research was supported by the research grants #021220CRP0122 “Development of highly sensitive MOS based nano-film gas sensors” from Nazarbayev University. Figure 1