Robust Conversion-Type Li/Garnet interphases from metal salt solutions

Garnet-type Li7La3Zr2O12 (LLZO) electrolytes show considerable potentials in solid-state Li metal batteries, yet the serious interfacial problem has hindered its practical application. Herein, we propose a facile strategy to construct conversion-type metal oxides (eg. PbO, ZnO or Co3O4) as lithiophilic layers on garnet surface from metal salt aqueous solutions. Robust garnet/Li interface and greatly reduced interfacial resistance to as small as similar to 10 Omega cm(2) can be obtained. Combined with experimental analysis and theoretical calculation (Delta G), the mechanism of lithiophilicity of different metal oxides was explained. The mixed ionic and electronic conductive interlayer which can lead to uniform Li-ion flow is superior to the electronic conductive metal interlayer with poor ionic conductivity causing gradual failure of the interface. As expected, the Li vertical bar PbO/LLZTO/PbO vertical bar Li cells show the improved critical current density of 1.1 mA cm(-2) and excellent cycling stability for 1000 h at 0.3 mA cm(-2). With PbO modified garnet, LiNi0.5Co0.2Mn0.3O2 vertical bar garnet vertical bar Li cells operate well at room temperature and allsolid-state LiFePO4/PEO vertical bar garnet vertical bar Li cells run stably at 0.3 mA cm(-2) for at least 100 cycles at 60 degrees C.

Automated summary

By constructing lithiophilic layers on the garnet surface, robust garnet/Li interfaces and greatly reduced interfacial resistance can be achieved. A mixed ionic and electronic conductive interlayer is shown to be superior to an solely electronic conductive metal interlayer, allowing for uniform Li-ion flow.