Supporting Information
A novel coral-like garnet for high-performance PEO-based all solid-state batteries
Figure S1: Morphologies of LALZO with different nucleating agent at different stage of calcine Scale bar (3 μm).
The effect of GO in fabricating C-LALZO can result in two points: 1. The high specific area of GO provides more active sites for metal cations to adhere; 2. The abundant functional groups on the surface of GO have a strong attraction to metallic cations. To investigate the formation mechanism of C-LALZO, the functional groups on the surface of GO was removed by hydrothermal method. To prevent
GO-agglomeration after being reduced, excess PEG-2000 as dispersant was added.
Furthermore, another contrast group with pure PEG-2000 was developed to eliminate the effect of PEG. As presented in Fig. S1, SEM of C-LALZO shows when residual water was removed at 200°C, compare to the other two samples, the precursor of sample with GO exhibits a honeycomb-like morphology while there is no obvious honeycomb-like structure in the sample with rGO+PEG or PEG. In addition, there are smooth plant on one side of honeycomb-like precursor in sample with GO. After the temperature increased to 500°C, the precursors gradually shrank due to the decomposition of citric acid and GO. At 800°C, the SEM images presents C-LALZO have been developed in sample with GO. Whereas, there are no obvious coral like LALZO structure can be found in the other two samples. The above results suggest the formation of C-LALZO results from the strong attractive force between abundant functional groups and metallic cations.
Figure S2: XRD patterns of composite electrolytes with different coral LALZO contents
Figure S3. EIS of pure PEO electrolyte
The calculated ionic conductivity is 6×10−6 S cm−1
Figure S4. I-t curves of Li/PLC/Li cells at a potential of 10 mV at 60°C, (inset) EIS spectra of the same cell before and after polarization.
The lithium ion transference number (TLi+
) is measured by DC polarization and AC electrochemical impedance spectroscopy before and after polarization is measured to calculate the lithium ion transfer. A typical time dependence of the ionic current of a PLC and Nyquist plots of the lithium symmetric cells before and after polarization are shown in Fig. S4. The calculated value of TLi+ of the PLC is 0.26.
Figure S5: LSV of PLB and PLC with 20 wt% LALZO
Figure S6. (a) Cycling performance and (b) charge-discharge voltage profiles at 0.1 C and 60°C of LCO/PLC/Li.
