Nanostructured Garnet-Type Solid Electrolytes for Lithium Batteries: Electrospinning Synthesis of Li₇La₃Zr₂O₁₂ Nanowires and Particle Size-Dependent Phase Transformation

Abstract

Lithium lanthanum zirconate (LLZO) is a promising ceramic solid electrolyte for all-solid-state lithium batteries with improved safety characteristics. However, the different phases of LLZO differ in lithium ionic conductivity by several orders of magnitude, with extrinsic dopants often required to stabilize the high conductivity cubic phase. Here we show that cubic LLZO can be stabilized at room temperature in nanostructured particles without the use of extrinsic dopants. LLZO nanowires were synthesized using electrospinning and formed cubic phase materials after only 3 h calcination at 700 °C. Bulk LLZO with tetragonal structure was transformed to the cubic phase using particle size reduction via ball milling. Heating conditions that promoted particle coalescence and grain growth induced a transformation from the cubic to tetragonal phases in both types of nanostructured LLZO. Detailed structural characterization with XRD and TEM were performed to understand the LLZO formation processes and phase transformations. This work demonstrates another strategy, namely the use of nanostructuring, as an alternative to extrinsic doping for obtaining cubic phase LLZO.

Toward the Scale‐Up of Solid‐State Lithium Metal Batteries: The Gaps between Lab‐Level Cells and Practical Large‐Format Batteries

“…Liu [64] et al recorded the advanced methods for the deposition of the LLZO thin films. In addition to the conventional sintering method, [65] chemical vapor deposition (CVD), [66] electrospinning, [67] aerosol deposition, [68] and pulsed laser deposition [69] are introduced into LLZO fabrication with different morphologies. Nevertheless, the microstructures of obtained LLZO are different via different synthesis routes, resulting in different ionic conductivities and electrochemical performances.…”

Universal Soldering of Lithium and Sodium Alloys on Various Substrates for Batteries

“…One of the most attractive and effective strategies to develop practical Li metal batteries is to use solid‐state electrolytes (SSEs) because of their nonflammability and mechanical strength to block dendritic Li growth . Among the many SSEs studied, the cubic garnet phase SSEs are more attractive because of their excellent chemical stability, high ionic conductivities, and wide electrochemical potential window …”

“…[5,6] Among the many SSEs studied, [7][8][9][10][11][12][13][14] the cubic garnet phase SSEs [15][16][17][18][19][20][21] are more attractive because of their excellent chemical stability, [22,23] high ionic conductivities, [15,16,[24][25][26] and wide electrochemical potential window. [5,6] Among the many SSEs studied, [7][8][9][10][11][12][13][14] the cubic garnet phase SSEs [15][16][17][18][19][20][21] are more attractive because of their excellent chemical stability, [22,23] high ionic conductivities, [15,16,[24][25][26] and wide electrochemical potential window.…”

Ni–Al–Cr superalloy as high temperature cathode current collector for advanced thin film Li batteries

“…17 Because the optimum crystallization temperature for cathode materials such as LMNO 18 and LiCoO 2 (LCO), 19,20 and fast solid-state electrolytes such as the garnettype Li 7 La 3 Zr 2 O 12 (LLZO) and perovskite-type Li 0.17 La 0.61 TiO 3 (LLTO) are at least 700-750 C in order to get the desired phases and attain high ionic conductivity. [21][22][23][24] The commonly used CCs such as Al cannot withstand such high temperatures in an oxidizing atmosphere without melting or becoming highly insulating. Stainless steels (SSs), on the other hand, are a tempting choice due to their oxidation resistance at high temperature, but it has been shown for LiMn 2 O 4 that both Fe and Cr diffuse into the cathode degrading its performance.…”