Enhanced Li⁺ conduction in perovskite Li_3xLa_2/3−x□_1/3−2xTiO₃ solid-electrolytes via microstructural engineering

Abstract

To realize all-solid-state lithium batteries, it is necessary to develop solid electrolytes with high ionic conductivity and stability. A total Li+ conductivity as high as 4.8 × 10−4 S cm−1 can be achieved for perovskite Li3xLa(2/3)−x□(1/3)−2xTiO3 at 25 °C via microstructural modifications.

Electrochemical and mechanical stability of LixLa0.557TiO3‐δ perovskite electrolyte at various voltages

“… The relatively high σ b of 1.65 × 10 −3 S/cm in this work could be due to the pure cubic structure and low porosity. By comparison, the grain‐boundary conductivity in literatures is very dispersed, and distributes from 6 × 10 −6 S/cm to 9.2 × 10 −4 S/cm Similar with the bulk σ b , σ gb was also influenced by composition, phase purity and porosity. However, σ gb was obviously affected by the grain size .…”

“…By comparison, the grain‐boundary conductivity in literatures is very dispersed, and distributes from 6 × 10 −6 S/cm to 9.2 × 10 −4 S/cm Similar with the bulk σ b , σ gb was also influenced by composition, phase purity and porosity. However, σ gb was obviously affected by the grain size . The grain size of Li 3 x La 2/3‐ x TiO 3 systems is normally 1‐3 μm, and a large grain size of 10 μm corresponds to a very high σ gb of 9.2 × 10 −4 S/cm…”

Multilayered, Bipolar, All‐Solid‐State Battery Enabled by a Perovskite‐Based Biphasic Solid Electrolyte

“…Specifically,t he incorporation of solid particles is known to promotei onic conduction by weakening the interactions between mobilei ons and polymer chains. [35,37] In addition, the LLTO material synthesized in this study exhibits a s value as high as 2.4 10 À4 Scm À1 anda nL i + transferencen umber of 0.99999; [31] therefore, highly conductiveL LTOc an increaset he concentration of mobile Li + ions and provide facile conduction pathways through the LLTO particles, as well as at the interfaces between LLTO and PEO. The degree of crystallinity (a)o ft he polymer contained in am ixture can be estimated from Equation (1): for 100 %c rystalline PEO), [41] respectively.A ss ummarized in Ta ble S1 in the Supporting Information, the DH m value decreases with increasing LLTO content,w hich indicates that LLTO suppresses polymer crystallization, and thus, improves the conductingp roperties of PEO.…”

“…[5][6][7][8][9][10][11][12][13] However,t here are practical challenges that hindert heir successful application in large-scale bipolar ASSBs. [26][27][28][29][30][31][32] Despite all of these merits,h owever,t hey require ah igh-temperatures intering process to achieve acceptable ionic conductivity.T he high-temperature process not only causesd eleterious reactions between the electrolytes and electrodes and damage to other components, but also makes it difficult to fabricate thin and large-area electrolyte sheets for ASSBs. [21][22][23][24][25] Therefore, utmost caution mustb ee xercised when synthesizing/handling materials and fabricating batteries.…”

“…Although sulfide-baseds olid electrolytes, such as Li 7 P 3 S 11 (LPS), Li 10 GeP 2 S 12 (LGPS),g lass ceramics, and Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 ,p ossessh igh ionic conductivities at room temperature (2.5 10 À2 to 1.0 10 À3 Scm À1 ), they suffer from chemical/structural instability against moisture. [28][29][30][31][32] Furthermore, hard and brittle features of the sintered electrolyte sheets inhibitc lose contact betweent he electrolyte and electrode;t hus leading to both poor electrochemical performance and reliability of ASSBs. Oxide-based solid electrolytes, fore xample, perovskite-, NASICON-, and LISI-CON-based compounds, offer many advantages, such as good chemical/structural stabilityi nahumid atmosphere and aw ide operating temperature range, over sulfides (although garnettype oxides are known to have chemical instability against moisture, resulting in the formation of LiOH and Li 2 CO 3 ).…”