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Conventional liquid electrolyte batteries suffer from low energy density and short cycle life.
Research is turning to solid-state lithium metal batteries (SSEs) based on Li7 La3 Zr O212 (LLZO) because of their higher energy density, longer cycle life, safety, non-flammability, and high temperature resistance.
High-density LLZO Nanofiber Membrane with a thickness of less than 50 μm was successfully synthesized by rapid Joule heating technology with a density of 5.08 g/cm³, showing a pure cubic phase LLZO structure and excellent bending strength of 139 MPa.
Through a series of experiments with different sintering times and temperatures (15-105 seconds and 1100-1300°C), it was determined that sintering at 1200°C for 45 seconds can obtain high-density, phase-pure LLZO membranes.
The chemical and structural evolution of the LLZO membrane during sintering was analyzed using multi-level material characterization tools such as in situ synchrotron X-ray diffraction (SXRD) and thermogravimetric analysis-mass spectrometry (TGA-MS).
LLZO Nanofiber Membrane exhibits a critical current density of up to 12.5 mA cm² in a lithium/LLZO/lithium symmetric cell configuration, maintaining excellent conductivity at higher currents.
At a current density of 1 mA cm², the LLZO membrane can maintain superior cycling stability for more than 250 cycles, demonstrating long-term reliability.
The membrane can still maintain good performance under the area capacity limit of 1 mAh cm², which is suitable for practical applications.
Figure 1: Shows the ultrafast sintering temperature curve and SXRD image of LLZO Nanofiber Membrane, as well as the SEM top view and cross-sectional image of LLZO Nanofiber Membrane.
Figure 2: Shows the SXRD and TGA-MS images of LLZO Nanofiber Membrane heat-treated in an inert atmosphere.
Figure 3: Shows the surface chemical composition analysis of LLZO Nanofiber Membrane after rapid Joule heating.
Figure 4: Shows the electrochemical performance of Li/LLZO/Li symmetric cells at 75°C.
Figure 5: Electrochemical performance of Li/LLZO/Pyr-IHF full cell is shown.
High-density, structurally self-supporting LLZO Nanofiber Membranes with a thickness of 45 μm were successfully prepared by rapid Joule heating technique.
The LLZO membranes sintered at 1200°C for 45 seconds were mechanically stable, phase pure, and had a density of up to 5.08 g/cm³, close to 99% of the theoretical value.
These Nanofiber Membranes exhibited excellent mechanical strength of 139 MPa.
The heat-treated LLZO Nanofiber Membranes showed a lithium-ion conductivity of 0.55 mS-cm-1 in the electrochemical performance evaluation, a high CCC of up to 12.5 mA-cm-2 in the Au/LLZO/Au symmetric cell, and a cycling stability of more than 250 hours at 1 mA-cm-2 and a limiting capacity of 1 mAh-cm-2 at 75°C.
Demonstrated excellent electrochemical cycling stability in full cell configuration, maintaining 94 mAh-g-1 capacity after 300 cycles
Electrospinning Nanofibers Article Source:
https://onlinelibrary.wiley.com/doi/10.1002/advs.202412370
