Ni-Particle-Embedded Bilayer Gel Polymer Electrolyte for Highly Stable Lithium Metal Batteries

Li metal is an ideal anode material for batteries based on Li ion because of its high theoretical specific capacity and low redox potential. However, the repeated formation and collapse of solid electrolyte interphase layer on its surface results in poor cycling performance leadable short lifetime and safety issues. To solve these problems, we introduced a bilayer consisting of a Ni/polymer composite electrolyte (NPCE). A Li|Li symmetrical cell system with an NPCE showed a superior stability tolerable voltage range of ±15 mV during 1000 cycles even at a high current density of 20 mA cm–2. Additionally, the NPCE-applied Li metal batteries (LMB) maintained the specific capacity of 85.16% after 500 cycles at a high current density rate of 5C; meanwhile, the specific capacity of an LMB, which used a conventional polyolefin separator, faded to 52.34%. Thus, the NPCE is an excellent gel polymer electrolyte for stable SEI layer control on the Li surface during cycling.