Interfacial phenomena between lithium ion conductors and cathodes

Abstract

Nanocomposites of a lithium ion conductor Li1.3Al0.3Ti1.7(PO4)3 and electrode materials (TiO2 and FePO4) were prepared to investigate interfacial structure and ionic conductivity at the interface between the solid electrolyte and electrode materials. It was revealed that lithium ions in the solid electrolyte were attracted to the cathode materials with increasing electrode potential, which increases lithium vacancies in the solid electrolyte.For the FePO4 containing composites, due to the high electrode potential, lithium transfer across the interface and ionic conduction through the cathode materials was remarkable.The results suggest that severe lithium depletion occurs and interfacial resistance is large at the interface of high ionic conductors and cathode materials. The space charge layer thickness is also discussed.

Local structure and composition change at surface of lithium-ion conducting solid electrolyte

“…We have so far studied the local structure at the interfacial region by fabricating nano-composites of active materials and solid electrolytes, and confirmed that the interfacial region with distorted lattice ranges for at least 20-50 nm in thickness [13,14].…”

“…In addition, we observed that ball-milling of a poor ionic conductor (Li 2 SiO 3 , LSO) resulted in increase in ionic conductivity without change in activation energy [13,17]. This is interesting because size reduction of solid electrolyte particles generally increases grain boundary resistance, which is generally observed for high ionic conductor [14]. The enhanced ionic conductivity in the nano-LSO may be explained by three plausible mechanisms.…”

“…On the other hand, intrinsic factors are unclear. Three plausible mechanisms have been reported as an origin of the intrinsic interfacial resistance: formation of interphases [9,12], depletion of mobile ions due to space charge layer (SCL) [1,13,14], and distortion of crystal lattice because of lattice mismatch [12]. According to theSCL model, theSCL is about twice ofDebye length in thickness and is calculated to be less than 1 nm for high ionic conductors.…”

Development of rechargeable lithium–bromine batteries with lithium ion conducting solid electrolyte

“…As a result of the ion transfer, Li þ -depletion layer (space charge layer) is formed in the solid electrolytes [27]. The decreased Li þ in the solid electrolytes adjacent to the interface would result in the increased interfacial resistance [26]. This would be also applied for active materials solutions.…”

Origin of High Interfacial Resistances in Solid‐State Batteries: Interdiffusion and Amorphous Film Formation in Li0.33La0.57TiO3/LiMn2O4 Half Cells

“…However, the poor ionic conductivity of SEs and the high interfacial resistance between SEs and electrodes are two drawbacks for solid state lithium ion batteries, which could lead to low power density and poor cycling performance of SSBs. [8] Recently, great progress has been made in improving the ionic conductivity of SEs. Kanno's group reported a lithium superionic conductor Li 10 GeP 2 S 12 with ionic conductivity of 10 À 2 S/cm, [9] which is comparable to a liquid electrolyte.…”