Display omitted •Smectic nanostructured electrolytes were prepared for solvent-free li-ion batteries.•High content LiBF4 formed dynamic lamellar conducting channels in smectic electrolytes.•Smectic electrolytes showed robust stability and high efficiency for li-ion battery.•Phase transition of electrolytes could thermally switch on/off li-ion batteries.•The work gave new light on developing efficient and smart electrolytes for li-ion battery. Developing electrolytes with desirable electrochemical performance and robust stability remains a huge challenge to meet the efficiency and durability demands of energy storage and conversion devices. Herein, the potential of ionic liquid crystals as high-performance electrolytes is demonstrated. Smectic ionic liquid crystals only consisting of conventional C14MimBF4 and LiBF4 are designed and prepared as electrolytes for solvent-free lithium-ion batteries. C14MimBF4 has good miscibility with LiBF4 to form smectic liquid crystals. LiBF4 is highly concentrated by C14MimBF4 layers in the smectic electrolytes to form dynamic lamellar conducting channels, which enable considerable ion conductivities of 10–4 ∼ 10–3 S cm−1. The smectic electrolytes possess robust cyclic stability and energy conversion efficiency in Li/LiFePO4 batteries, which show a charge/discharge capacity of 154.7 mA h g−1 at a 1 C current density, as well as stable performance after 100 charge/discharge cycles even at 80 ℃. Additionally, the phase transition behavior of the electrolytes can be applied as a smart switch to thermally tune on/off the batteries. The electrolytes show almost no charge/discharge behavior under crystal phase, but automatically operate efficiently with charge/discharge capacities >150 mA h g−1 once entering the smectic phase. The present work sheds new light on developing high-performance and smart electrolytes for solvent-free Li-ion batteries.