Nature Communications
·
2020
·Vol. 11
·期 1
·1-10
·
IF 12.121
Yang Ya-Nan,Li Ying-Xiang,Li Yi-Qiu,Zhang Tao
Lithium garnets have been widely studied as promising electrolytes that could enable the next-generation all-solid-state lithium batteries. However, upon exposure to atmospheric moisture and carbon dioxide, insulating lithium carbonate forms on the surface and deteriorates the interfaces within electrodes. Here, we report a scalable solid sintering method, defined by lithium donor reaction that allows for complete decarbonation of Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) and yields an active LiCoO 2 layer for each garnet particle. The obtained LiCoO 2 coated garnets composite is stable against air without any Li 2 CO 3 . Once working in a solid-state lithium battery, the LiCoO 2 -LLZTO@LiCoO 2 composite cathode maintains 81% of the initial capacity after 180 cycles at 0.1 C. Eliminating CO 2 evolution above 4.0 V is confirmed experimentally after transforming Li 2 CO 3 into LiCoO 2 . These results indicate that Li 2 CO 3 is no longer an obstacle, but a trigger of the intimate solid-solid interface. This strategy has been extended to develop a series of LLZTO@active layer materials.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2015
·
IF 6.217
Biyi Xu,Huanan Duan,Wenhao Xia,Yiping Guo,Hongmei Kang,Hua Li,Hezhou Liu
A multistep sintering schedule is developed to synthesize Li 7 La 3 Zr 2 O 12 (LLZO) doped with 0.2 mol% Al 3+ . The effect of sintering steps on phase, relative density and ionic conductivity of Al-doped LLZO has been evaluated using powder X-Ray diffraction (XRD), scanning electron microscopy (SEM), 27 Al magic spinning nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that by holding the sample at 900 °C for 6 h, the mixture of tetragonal and cubic garnet phases are obtained; by continuously holding at 1100 °C for 6 h, the tetragonal phase completely transforms into cubic phase; by holding at 1200 °C, the relative density increases without decomposition of the cubic phase. The Al-LLZO pellets after multistep sintering exhibit cubic phase, relative density of 94.25% and ionic conductivity of 4.5 × 10 −4 S cm −1 at room temperature . Based on the observation, a sintering model is proposed and discussed.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Saisai Zhang,Hailei Zhao,Jie Wang,Tao Xu,Kangkang Zhang,Zhihong Du
As promising next generation energy storage system, all solid state lithium batteries offer great potential for achieving high energy density and improved safety over lithium batteries with liquid counterpart. Dense microstructure with high ionic conductivity are prerequisites for solid electrolyte. The promising Li-garnet electrolyte suffers from poor sinterability, which results in porous structure and large grain boundary resistance. Herein, we report that the poor sinterability of garnet Li 7 La 3 Zr 2 O 12 is most likely related to the Li 2 CO 3 formed on particle surface, and SiO 2 is an efficient additive to scavenge the surface Li 2 CO 3 and so significantly improve the densification of electrolyte. The reaction product Li 4 SiO 4 of SiO 2 with Li 2 CO 3 is a Li-ion conductor, which exists at grain boundary and so can facilitate the grain boundary lithium ion diffusion. An addition of 1 mol.% SiO 2 , with respect to the total lithium content in Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO), significantly increases the relative density of LLZTO pellet by 28% and the conductivity by one order of magnitude, reaching 3.84 × 10 −4 S cm −1 at room temperature by a conventional solid state sintering. A symmetric lithium cell assembled with such dense LLZTO electrolyte can cycle well for 260 h compared with unmodified LLZTO running only for 72 h before short-circuit.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Shufeng Song,Yongmin Wu,Zhencai Dong,Fan Deng,Weiping Tang,Jianyao Yao,Zhaoyin Wen,Li Lu,Ning Hu,Janina Molenda
Lithium garnets are considered as advanced solid electrolytes for safe and high-energy-density solid-state lithium batteries . A multi-substituted strategy illustrating in this work is substitution of Li by Ga and Zr by Ta/Ba, therefore stabilizing and densifying the cubic lithium garnets thus improving the ionic conductivities . The influence of Ga substitution on garnet phase, microstructure and conductivity of Li 6.7-3x Ga x La 3 Zr 1.55 Ta 0.4 Ba 0.05 O 12 garnets is systematically studied. The developed multi-substituted garnet-type electrolytes demonstrate high ambient-temperature conductivity of 1.02 × 10 -3 S cm -1 . Moreover, the multi-substituted garnet reveals impressive capability of alleviating lithium metal dendrites over 800 h under current of 0.01 mA cm -2 to 0.5 mA cm -2 , promising solid-state battery applications.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
产品关联
DOI
高影响因子
SOLID STATE IONICS
·
2013
·
IF 2.046
Yiqiu Li,Yang Cao,Xiangxin Guo
The lithium garnet ceramic has been considered as one of promising solid-state electrolytes for secondary lithium batteries . However, improvement of its ionic conductivity is hindered by the high porosity related to the severe volatilization of lithium components during sintering. In order to find the solution for this problem, Li 2 O additives in concentration of 2–8 wt.% were introduced into the cubic Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) at the solid-state reaction processes. It is found that the Li 2 O additives lead to formation of glassy-like phases at the grain boundaries related to the liquid-phase sintering behavior, which eliminates the residual pores therein and increases the relative density from 91.5% to 97.3%. Measurement of conductivity indicates that 6 wt.% is the optimum concentration of Li 2 O which leads to an ionic conductivity of 6.4 × 10 − 4 S cm − 1 at room temperature . This value is approximately 3 times larger than that of the ceramic without the additive.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2013
·
IF 4.675
Yiqiu Li,Zheng Wang,Chilin Li,Yang Cao,Xiangxin Guo
High density (∼96%) garnet-type Al-contained Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO-Al) solid electrolytes are prepared by conventional solid-state reaction and the following flowing oxygen sintering process . An overall ionic conductivity as high as 7.4 × 10 −4 S cm −1 at 25 °C is achievable, remarkably higher than that obtained by sintering in other atmospheres. The dependence of density and conductivity of solid electrolytes on sintering under different oxygen partial pressures is discussed. Atmosphere sintering is proved to be an effective method to improve the relative density of lithium oxide ceramics .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）