Dual-layer hybrid solid electrolyte for improved interfacial stability in solid-state lithium batteries

초록

Hybrid solid electrolytes (HSEs), which combine the advantages of polymers and ceramics, offer great potential for use in high-performance solid-state lithium batteries (SSLBs) owing to their high ionic conductivities and excellent interfacial compatibilities. However, single-layer electrolytes often suffer from performance degradation caused by interfacial incompatibility with electrodes. In this work, we design a dual-layer structured electrolyte that simultaneously satisfies the distinct interfacial requirements of both the cathode and lithium metal anode, thereby significantly enhancing the electrochemical performance. Li,.3Al0.3Ti,.7(PO4)3 (LATP) was doped with 0.075 mol of Zr to improve Li+ diffusion kinetics, and the resulting LAZTP dual HSE exhibited a high ionic conductivity of 5.0 & times; 10-4 S cm- 1, as well as improved mechanical properties with a tensile strength of 6.32 MPa and Young's modulus of 30.9 MPa-both superior to those of the single-layer electrolyte. The duallayer architecture also enabled stable Li plating/stripping behavior for 500 h at 0.2 mA cm- 2. When applied to LiFePO4 (LFP)/LAZTP dual HSE/Li SSLBs, the dual-layer electrolyte delivered a discharge capacity of 155.7 mAh g- 1 at 0.5C, an excellent capacity retention of 92.6% after 200 cycles, and an average Coulombic efficiency of 99.4%.

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