A safe anode-free lithium metal pouch cell enabled by integrating stable quasi-solid electrolytes with oxygen-free cathodes

The severe safety risks arising from notorious lithium dendrites growth and radical oxygen-releasing cathodes in organic liquid electrolytes under abuse conditions, hamper the practice application of lithium metal batteries, especially operated with zero lithium excess (anode-free cells, AFC). Herein, we report a stable quasi-solid electrolyte (QSE) composed of thermoplastic polyurethane and nano-fumed silica aerogels with high mechani-cal robust, superior hydrophobicity, exceptional thermal and electrochemical stability, as well as the capability to achieving dendrite-free deposition behaviors. Furthermore, the introduction of oxygen-free lithium sulfide as cathode fundamentally avoids the lattice oxygen release from the cathode as well as stable redox free of reactive Li metal and oxygen species, further ensure AFC reliability. As a result, a superior stability of 100 cycles with a high average Coulombic efficiency of over 98.6% can be achieved in the integrative quasi-solid and oxygen-free cathode AFC. As a proof of practical application, such AFC pouch cells with safe configuration exhibits superior reliability against mechanical damage, electrical and thermal abuse condition. This safe configuration of AFC based stable QSE and oxygen-free cathodes paves the way for safe LMBs towards the various application con-ditions, even under abuse circumstance.

Automated summary

A stable quasi-solid electrolyte (QSE) composed of thermoplastic polyurethane and nano-fumed silica aerogels has been developed, which exhibits high mechanical robustness, superior hydrophobicity, exceptional thermal and electrochemical stability, and the ability to achieve dendrite-free deposition behaviors. Additionally, the introduction of oxygen-free lithium sulfide as cathode fundamentally avoids lattice oxygen release, ensuring stable redox reactions without reactive Li metal and oxygen species. The integrative quasi-solid and oxygen-free cathode AFC demonstrates superior stability with 100 cycles and a high average Coulombic efficiency of over 98.6%.