Self assembled electron blocking and lithiophilic interface towards dendrite-free solid-state lithium battery

Abstract

The poor interfacial contact is one of the biggest challenges that solid-state lithium batteries suffer from. Reducing the solid-state electrolyte surface energy by transforming the interface from lithiophobic to lithiophilic is effective to promote the interfacial contact, but electronic conductive interphases usually increase the risk of electron attack, thus leading to uncontrollable Li dendrite growth. Herein, we propose a self-assembled thermodynamic stable LiI interphase to simultaneously improve the interfacial contact between the garnet electrolyte Li7La3Zr2O12 (LLZO) and Li anode, and prohibit the electron attack. The direct contact between LLZO and Li and the high temperature Li melting process was ascribed to Zr4+ reduction, which facilitated Li dendrite formation and propagation. With the modification of the high lithiophilic I2 thin film, the area specific interfacial resistance of LLZO/Li was reduced from 1525 Ω/cm2 to 57 Ω/cm2. More importantly, LLZO was protected from being reduced due to the outstanding electronic insulativity of the LiI interphase, which leaded to a high critical current density of 1.2/7.0 mA/cm2 in the time/capacity-constant modes, respectively.