Solid-state electrolytes (SSEs) have been attached widespread attention as next-generation materials as far as safety and energy density concerned, but they are severely plagued by the limited oxidative potential, poor physical contact with electrodes and lithium dendrite growth. Organic ionic plastic crystal (OIPC), solid analogues of ionic liquids (ILs), are intrinsic non-flammable, non-volatile and compatible with lithium anode. In the present work, an electrochemical durable polyimide plastic crystal electrolyte (PPCE, up to 5.5 V vs Li/Li+) can be obtained as a result of the good interaction between OIPC and Li salt. Also, the soft, deformable property of OIPC and proper melting point of OIPC-Li salt endure good physical contact with electrodes. Consequently, solid-state dendrite-free Li/PPCE/Li cells show an ultralong cycle life over 1000h under 1.0 mA cm− 2, and room temperature high-voltage Li/PPCE/ LiNi0.6Co0.2Mn0.2O2 cion cells achieve a capacity retention of 80% after 633 cycles under 1.0 C and ~ 5.0V class Li/PPCE/LiNi1.5Mn0.5O4 coins cells keep 91% discharge capacity after 100 cycles under 1.0 C at 25 ℃. The ionic and non-volatile nature of OIPC ensure the safety of PPCE so that it can past the harsh penetration test under practical conditions. Furthermore, the PPCE- based pouch cell shows good flexibility, acceptable rate performance and a high energy density of 223.1Wh kg− 1(based on merely electrolyte and electrodes). It is anticipated that our work provides an avenue for next-generation solid-state batteries.