Influence of microstructure and AlPO₄ secondary-phase on the ionic conductivity of Li1.3Al0.3Ti1.7(PO4)3 solid-state electrolyte

Abstract

A ceramic solid-state electrolyte of lithium aluminum titanium phosphate with the composition of Li[Formula: see text]Al[Formula: see text]Ti[Formula: see text](PO[Formula: see text] (LATP) was synthesized by a sol–gel method using a pre-dissolved Ti-source. The annealed LATP powders were subsequently processed in a binder-free dry forming method and sintered under air for the pellet preparation. Phase purity, density, microstructure as well as ionic conductivity of the specimen were characterized. The highest density (2.77[Formula: see text][Formula: see text] with an ionic conductivity of [Formula: see text] (at 30[Formula: see text]C) was reached at a sintering temperature of 1100[Formula: see text]C. Conductivity of LATP ceramic electrolyte is believed to be significantly affected by both, the AlPO4 secondary phase content and the ceramic electrolyte microstructure. It has been found that with increasing sintering temperature, the secondary-phase content of AlPO4 increased. For sintering temperatures above 1000[Formula: see text]C, the secondary phase has only a minor impact, and the ionic conductivity is predominantly determined by the microstructure of the pellet, i.e. the correlation between density, porosity and particle size. In that respect, it has been demonstrated, that the conductivity increases with increasing particle size in this temperature range and density.

Insights into a layered hybrid solid electrolyte and its application in long lifespan high-voltage all-solid-state lithium batteries

“…30 The synthesis of the Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 powder and the preparation of ceramic electrolyte pellets were performed as reported in our previous studies. 6,16 The ceramic pellets used as substrates for the polymer electrolyte coating were prepared from the LATP powder pre-calcined at 800 C via a pressingsintering process, which including uniaxial die pressing, densication by cold isostatic pressing at 504 MPa for 30 seconds, and subsequent sintering at 1100 C for 8 hours. The thickness and surface roughness of the LATP pellets were controlled by polishing with sandpapers (P800 and P1200).…”

“…Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (denoted as LATP) is an attractive solid electrolyte with a scalable production procedure for the possible commercialization of ASSBs, owing to its competitive ionic conductivity (close to 1 mS cm À1 at room temperature) and its low sensitivity against an oxygen/moisture atmosphere compared to other ceramic ion conductors like sulde-based glass electrolytes or garnet electrolytes. [15][16][17] Unfortunately, LATP degrades when in contact with the lithium metal since Ti 4+ will be reduced to Ti 3+ , leading to a decomposed electrolyte surface with high resistance for Li + migration. 15 Moreover, like most ceramic electrolytes, poor mechanical contacts and/or microcracks may occur between the LATP electrolyte and electrodes during battery preparation and operation, thus blocking percolation pathways for lithium ions.…”

An Advanced All Phosphate Lithium-Ion Battery Providing High Electrochemical Stability, High Rate Capability and Long-Term Cycling Performance

“…19,20 Among these phosphate-materials, monoclinic lithium vanadium phosphate Li 3 V 2 (PO 4 ) 3 (LVP) is known to have two electrochemical windows for operation, 3.0 ∼ 4.3 V vs. Li + /Li and 3.0 ∼ 4.8 V vs. Li + /Li, resulting in different theoretical gravimetric capacities of 131 mAh · g −1 and 197 mAh · g −1 , respectively. 18 The * Electrochemical Society Member.…”

“…18 More than that, phosphate materials are also believed to be superior candidates of anode and solid electrolyte for lithium-ion battery owing their intrinsic high ionic conductivity and stability. 19,20 Among these phosphate-materials, monoclinic lithium vanadium phosphate Li 3 V 2 (PO 4 ) 3 (LVP) is known to have two electrochemical windows for operation, 3.0 ∼ 4.3 V vs. Li + /Li and 3.0 ∼ 4.8 V vs. Li + /Li, resulting in different theoretical gravimetric capacities of 131 mAh · g −1 and 197 mAh · g −1 , respectively. 18 The * Electrochemical Society Member.…”

Single‐Phase All‐Solid‐State Lithium‐Ion Battery Using Li3V2(PO4)3 as the Cathode, Anode, and Electrolyte

“…In addition, the improvement of the bulk Li conductivity and cell performance were also tried by Al substitutional doping for V in Li 3 V 2 (PO 4 ) 3 . Al is selected as a dopant because it is the typical dopant for the NASICON‐type high lithium‐ionic conductor . A schematic illustration of the experimental single‐phase lithium‐ion battery using Li 3 V 2 (PO 4 ) 3 is shown in Figure .…”