The thermal instabilities of deposited lithium with electrolytes in lithium-ion batteries are simulated by the reactions between metallic lithium with organic esters and ethers. Exothermic onset temperatures and enthalpy changes are measured and analyzed by differential scanning calorimetry. In this study, heat of reactions in lithium with eight different formations of esters and ethers are determined which are consistent to the data of lithiated graphite (LiC6) reacted with electrolytes in literature. Furthermore, violently exothermic reactions with enthalpy larger than 1,000 J g(-1) and onset temperature lower than 120 A degrees C are further conducted by the confinement test to verify the worst scenarios and consequences of lithium-ion batteries encountered any kind of abuses. Thermal instability of metallic lithium with organic esters in descending order determined to be Li + EB (70 A degrees C)> Li + MB (73.1 A degrees C)> Li + EA (90.8 A degrees C). Finally, thermal hazard data such as onset temperature, maximum self-heat rate, maximum temperature, and maximum pressure of lithium reacted with esters and ethers are compared, evaluated, and some conclusion and suggestions are made.