Hybrid solid electrolyte enabled dendrite-free Li anodes for high-performance quasi-solid-state lithium-oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium dendrite growth on Li anodes critically impairs lithium-oxygen (Li-O2) battery performance.
• Hybrid solid electrolytes (HSEs) are promising for mitigating dendrites but face challenges in balancing mechanical strength, flexible anode contact, and uniform ion distribution.
• Existing HSEs struggle to meet the simultaneous demands for high modulus, conformal contact with Li metal, and efficient Li+ transport.

Purpose of the Study:

• To design and develop a novel hybrid solid electrolyte (HSE) that addresses the contradictory requirements for stable lithium metal anodes in Li-O2 batteries.
• To investigate the structural and electrochemical properties of a core-shell HSE comprising rigid LAGP and flexible PVDF-HFP.
• To demonstrate the efficacy of the developed HSE in suppressing lithium dendrite formation and improving the cycling stability of quasi-solid-state Li-O2 batteries.

Main Methods:

• Fabrication of a hybrid solid electrolyte featuring a rigid Li1.5Al0.5Ge1.5(PO4)3 (LAGP) core and an ultrathin flexible poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) shell.
• Characterization of the HSE's mechanical properties, including Young's modulus, and its interfacial behavior with lithium metal.
• Electrochemical testing of the HSE in quasi-solid-state Li-O2 batteries, focusing on lithium deposition behavior and cycling performance.

Main Results:

• The developed HSE exhibits an ultra-high Young's modulus of 25 GPa, effectively suppressing lithium dendrite growth even at a deposition capacity of 23.6 mAh.
• The core-shell structure ensures uniform Li+ distribution and stable contact with the Li anode, preventing detrimental side reactions.
• The HSE-based quasi-solid-state Li-O2 battery demonstrates significantly enhanced cycling stability, achieving 146 cycles, over three times longer than batteries using gel polymer electrolytes.

Conclusions:

• The novel core@shell HSE design successfully overcomes the limitations of traditional hybrid solid electrolytes for lithium metal batteries.
• This approach provides a viable strategy for achieving dendrite-free lithium deposition and long-term stability in Li-O2 batteries.
• The findings offer valuable insights for the development of advanced solid electrolytes applicable to various battery chemistries, including sodium-oxygen systems.