One-step fabrication of garnet solid electrolyte with integrated lithiophilic surface

Abstract

Substituting nonflammable solid-state electrolytes for flammable liquid electrolyte is considered as the fundamental way to promote the safety of lithium metal batteries. However, the problem of poor interfacial contact between solid electrolyte and lithium has seriously hindered the development of solid-state batteries. This paper put forward an appealing strategy for constructing garnet solid electrolyte with a lithiophilic graphite interface via a one-step integrated spark plasma sintering method. With the existence of the integrated graphite modification layer, garnet turns lithiophobic into lithiophilic. And the lithiophilic graphite modification layer with high Li+-conductivity is conducive to homogenization of lithium-ion flux. Thus, the interfacial resistance decreases from 4351.6 to 26.2 Ω cm2 and accordingly the over-potential reduces from 500 to 30 mV, owing to the intimate interface contact, good interface compatibility and good lithium conductivity endowed by the integrated graphite modification layer. It shows excellent electrochemical stability for 900 h at 0.3 mA cm−2.