Production of Ta-Doped Li₇La₃Zr₂O₁₂ Solid Electrolyte with High Critical Current Density

Abstract

Solid-state electrolytes are key materials for developing high-safety solid-state Li-ion batteries. The garnettype Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte is one of the most promising solid electrolytes due to its high conductivity and feasible preparation in ambient air. Among several dopants, Tadoped LLZO (Ta-LLZO) delivers high stability against lithium metal and high conductivity, which attracts lots of researchers. However, production of Ta-LLZO ceramics is less problematic due to the complicated gas−liquid−solid sintering mechanism. This work aims to develop an efficient method to produce Ta-LLZO solid electrolyte ceramic pellets, including providing a stacking sintering method and optimizing the amount of excessive Li source, the wet milling duration, and the sintering temperature. First, a low-cost, efficient "gravel-separator" strategy is provided for multiple sintering of LLZO. Second, the Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 (Ta5) samples with different excessive Li levels (2, 4, 6, and 8%) are sintered at various sintering conditions of 1240 °C for 60 min, 1280 °C for 20 min, and 1320 °C for 2 min to search for the optimum excessive amount of Li. Third, Ta5 samples with optimized excessive Li (4, 6%) after milling for longer duration are sintered at 1280 °C for 30 min, 1300 °C for 10 min, 1320 °C for 10 min, 1320 °C for 30 min to finally optimize the preparation craft. After optimization, the Ta5 ceramics with excessive 4 and 6% Li sintered at 1320 °C for 10 min deliver homogeneous and dense crosssectional morphology, high conductivity of over 1 × 10 −3 S cm −1 at room temperature, and relative densities of above 96%. Furthermore, symmetric Li cells assembled with the Ta-LLZO solid electrolyte prepared with the optimized method deliver a critical current density of 1.28 mA cm −2 at 30 °C and over 1000 h of stable cycling at 0.2 mA cm −2 (0.2 mA h cm −2 ) at 30 °C.

Optimizing Li1.3Al0.3Ti1.7(PO4)3 Particle Sizes toward High Ionic Conductivity

“…As shown in Figure b and c, this hybrid cell delivered a high specific capacity of 157 mAh g –1 at the first cycle and maintained 140 mAh g –1 at the 60th cycle with a Coulombic efficiency of ∼100%. The total resistance of this hybrid Li–LFP battery was equivalent to that of other reports in the literature. , These results proved that the LATP ceramics prepared in this work could be applied in solid-state batteries.…”

“…Figure a displays the typical Nyquist plot of these batteries. In addition to the two semicircles relating to the ceramic ( R ceramic ) and interfacial charge transfer resistance ( R int ), the third semicircle linked to the charge transfer resistance of the LFP cathode ( R ct ) emerged before the low-frequency diffusion tail . As shown in Figure b and c, this hybrid cell delivered a high specific capacity of 157 mAh g –1 at the first cycle and maintained 140 mAh g –1 at the 60th cycle with a Coulombic efficiency of ∼100%.…”

“…On the other hand, sulfide electrolytes are very demanding to prepare as they are susceptible to moisture . Oxides with relatively high conductivities of 10 –4 –10 –3 S cm –1 are considered a potential SSE due to their ability to be prepared in air. − …”

Metal–Organic-Framework-Derived 3D Hierarchical Matrixes for High-Performance Flexible Li–S Batteries

“…Electrochemical energy storage, such as a supercapacitor or a lithium battery, has always been a hot topic in both the research and industry communities. − Lithium–sulfur (Li–S) batteries hold significant promise as the future of energy storage technology due to their high theoretical specific capacities of lithium (Li; 3860 mAh g –1 ) and sulfur (S; 1675 mAh g –1 ), as well as the low electrochemical potential of Li metal (−3.04 V vs reversible hydrogen electrode). − However, there remain challenging issues to be solved for practical applications and commercialization of Li–S batteries, such as uncontrollable lithium dendrite growth, needless side reactions, an unstable solid electrolyte interphase (SEI), and huge volume expansion of the Li metal anode . Additionally, lithium polysulfides (LiPSs) shuttling and inferior reaction kinetics have substantially limited electrochemical performance, triggering severe capacity degradation, poor rate property, and short cycling life .…”

20 mS cm−1 Li-argyrodite solid electrolyte produced via facile high-speed-mixing

“…1 All-solid-state batteries (ASSBs) are an alternative approach to solve the above problems. [2][3][4] Besides improved safety, additional potential advantages such as a broad electrochemical stability window and good compatibility with the lithium anode may be accessible and makes them strong contenders for next-generation commercial LIBs. 5,6 Sulfide solid electrolytes stand out from other solid electrolyte materials due to their very high ionic conductivity, making them prime candidates for ASSBs.…”