0428同步年報-2021-全

084 ACTIVITY REPORT 2021 low potential reveal the possible Li-ion conduction path. In α-LZC, the interconnect paths form a 3D percolating network with an effective migration barrier 0.803 eV ( Fig. 1(c) ). For the β-LZC structure, the paths within plane a - b are more favorable for Li-ion transport than for the interplane direction; the barrier for migration between adjacent planes is more than three times the barriers in plane a - b ( Fig. 1(f) ). An analysis of the ion conduction path partially explains the significant difference in the ionic conductivity between α-LZC and β-LZC. A test of humidity tolerance was performed employing X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and electrochemical impedance spectra. Figures 2(a) and 2(b) display the Zr-3d and Cl-2p XPS of the as-milled LZC and LZC exposed to humidity (5% RH for 24 h). The difference is insignificant. In tests of the electrochemical impedance spectra, the as-milled LZC well preserved its high conductivity after the humidity treatment ( Fig. 2(c) ), compared with a decrease almost an order of magnitude of Li 3 InCl 6 ( Fig. 2(d) ), which is the most humidity-tolerant chloride solid electrolyte reported before LZC. The raw materials for the mechanochemical synthesized Li 2 ZrCl 6 are orders of magnitude cheaper than those for other chloride solid electrolytes, which makes Li 2 ZrCl 6 at present the only chloride solid electrolyte with raw-material cost ($1.38/ m 2 ) below $10/m 2 (the threshold that ensures the competitiveness of all-solid-state batteries). The as-milled LZC was integrated as the solid electrolyte into all-solid-state cells with LiCoO 2 (LCO) or single-crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 particles (scNMC811) as the cathode and Li-In alloy as the anode. A thin layer of Li 6 PS 5 Cl (LPSCI) was applied to the surface of LZC to prevent the reaction between the anode and LZC. The electrochemical performance of the Li-In|LPSCl-LZ |scNMC811 cell is displayed in Fig. 3 . Being cycled at 0.1 C (1 C = 200 mA g –1 ) between 2.2 and 3.8 V, the cell delivered an initial Coulombic efficiency 90.3% and a discharge capacity 181 mA h g –1 ( Fig. 3(a) ). The rate capability of the Fig. 2 : Zr-3d (a) and Cl-2p (b) XPS of as-milled LZC before and after being exposed to the atmosphere with relative humidity 5%. Nyquist plots of the as-milled LZC (c) and Li 3 InCl 6 (d) before and after exposure to the atmosphere with relative humidity 5%. [Reproduced from Ref. 1]