Hybrid solid-state electrolytes for lithium metal batteries

Rechargeable Li metal batteries using Li metal anodes have attracted worldwide interest because of their high theoretical specific capacity (3860 mAh g-1) and lowest electrode potential (-3.040 V vs standard hydrogen electrode). The critical barriers limiting their commercial application include uncontrolled dendritic Li growth and the unstable Li-electrolyte interface resulting in short circuit and possible explosion. Solid-state electrolytes (SSEs) in place of liquid electrolytes are deemed a promising method to solve the safety concerns. Herein, we design and synthesise a series of hybrid solid-state electrolytes (HSSEs) that is Li-ion-conducting and electron insulating for the Li metal anode. The Ta-Nb co-doped ceramic powders with high ionic conductivity (1.04 ×10-3 S cm-1) dispersed in a polymer matrix could significantly enhance HSSEs mechanical properties, and decrease the polymer’s local crystallization, which is favourable for Li-ion transfer. The symmetric cell of PEO-LLZTNO HSSEs showed stable cycling with 56 mV polarization potential under 0.1mA cm2 for 1040 h at 60 oC, indicating a stable Li | PEO-LLZTNO 10% | Li interface with the ability to suppress lithium dendrite growth. This talk will also present a modified PVDF based HSSE that demonstrates excellent electrochemical performance when it is paired with a high-voltage cathode material NCM811. This cell can survive from the nail test in the air. The PVDF based HSSEs could power a portable game player and wearable ECG kit in the real application. Our research shows that the HSSEs would be promising candidates for the long lifespan safety batteries.