Interface engineering on cathode side for solid garnet batteries

Abstract

The garnet solid electrolyte battery confronts crucial challenges of electronic/ionic conduction inside the cathode and interfacial contact between the cathode and the electrolyte. In this report, a super ion/electron conductive LiCoO2 (LCO) material is fabricated by partially coating nano Li6.375La3Zr1.375Nb0.625O12 (LLZNO) electrolyte on LCO and then filling Super P carbons into the uncoated space. This configuration offers continuous ionically and electronically conducting networks inside the LCO cathode. In addition, an intermediate layer of N-Methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13-TFSI) is introduced in between the composite cathode and the garnet electrolyte to form a solid-state ionically conducting interphase during charge/discharge cycles. Through the above interfacial engineering, the solid garnet batteries based on LiCoO2 run as long as 400 cycles with the capacity retention of 80.2% at 0.2 C and 60 °C.