The impact induced penetration of liquid electrolyte and porous polymer separator can lead to the internal short-circuit of Li-ion batteries (LIBs), resulting in the fire and explosion. Here in this work, an electrochemically stable shear thickening electrolyte was developed to improve the safety of LIBs. The electrolyte was formulated by integration of (3-aminopropyl)triethoxysilane (APTES) modified glass fibers fillers and regular liquid electrolyte. The formulated electrolyte exhibited shear thickening behavior with the filler volume fraction greater than ∼28%. The transient behaviors of the shear thickening electrolyte under external impact with speed of 1.1–79 m/s (2.5–177 mph) were recorded with a high-speed camera and an instant increase of electrolyte viscosity upon large shear force was evidenced. The impact resistant electrolyte was further evaluated in the half-cell and full-cell LIBs. The cells exhibited excellent cyclability with a capacity retention of 95.2% after 500 cycles for Li-LFP (lithium metal anode and lithium iron phosphate cathode) half cells and 94.4% after 100 cycles for LTO-LFP (lithium titanate anode and lithium iron phosphate cathode) full cells. The results indicated that this impact resistant electrolyte has excellent electrochemical stability and is compatibility with commercial LTO and LFP electrode materials.