Matchmaker of Marriage between a Li Metal Anode and NASICON-Structured Solid-State Electrolyte: Plastic Crystal Electrolyte and Three-Dimensional Host Structure

The marriage between a Li metal anode and the solid-state electrolyte is expected to limit the safety risk of secondary batteries. However, dendrites and interfacial stability hinder the combination of Li metal anode and solid-state electrolyte. Herein, a plastic crystal electrolyte (PCE) and three-dimensional (3D) host structure played the role of a matchmaker in combining the solid-state electrolyte and Li metal anode. Succinonitrile cooperated with Li salt and Li6.4La3Zr1.4Ta0.6O12 nanosize powder and built a PCE interphase, which enhanced the interfacial stability between Li1.5Al0.5Ge1.5(PO4)3 and Li metal anode. To protect the soft PCE from the dendrite penetration, commercially sold Super P, carbon nanotube, KS6, and Ketjen black were co-heated with the melted Li metal. However, only KS6 built a 3D host in Li metal successfully because of its high graphitization and layered structure. Benefitting from the matchmakers, the solid-state batteries exhibited enhanced cycling stability.