MOF lamellar membrane-derived LLTO solid state electrolyte for high lithium ion conduction

Inorganic superionic conductor has been widely studied for potential application in all-solid-state lithium battery due to its high bulk ionic conductivity. However, the large grain boundary resistance and large thickness resulted from the poor film-forming ability, restricting its actual ionic conductivity. Inspired by the excellent film-forming ability and ultrathin thickness of 2D lamellar membrane, we reported an 11 μm-thick MOF lamellar membrane derived LLTO electrolyte (MLLTO). The electrolyte is prepared by impregnating LLTO precursors into the pores and interlayer channels of MOF lamellar membrane, followed by in situ sintering. It is demonstrated that the confined effect of interlayer channel in MOF lamellar membrane regulates the growth and arrangement of LLTO crystal, affording reduced grain boundary resistance. The porous structure of MOF nanosheet permits the construction of vertical Li+ transfer pathways between adjacent layers. Finally, MLLTO achieves a high ionic conductivity of 1.19 × 10−4 S cm−1 and ionic conductance of 0.215 S at room temperature, much higher than those of conventional LLTO electrolytes. The Li/MLLTO/Li symmetrical cell can stably cycle for 1000 h from 0.1 to 0.4 mA cm−2 at 60 °C without obvious polarization. The LFP/Li battery displays discharge capacity of 149.6 mAh g−1 at 0.5C after 200 cycles with low capacity decay of 0.04% per cycle.