Enhanced capacity and thermal safety of lithium-ion battery graphite anodes with conductive binder

Thermal safety is critical for marketable batteries. Numerous safety incidents from graphite anode instability impede lithium-ion battery (LIB) use for large-scale energy storage. Herein, we compare thermal safety and electrochemical performance of graphite anodes with commercial conducting polymer poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and standard polyvinylidene fluoride (PVDF) binders. Thermal analyses with differential scanning calorimetry (DSC) elucidates thermal runaway mechanisms. Reduced wettability of the PEDOT:PSS binder and lower specific surface area of the graphite anode composite contributes to less heat generation from solid electrolyte interphase (SEI) decomposition as compared to PVDF between 100 and 150ۥ°C, particularly when carbon black (CB) additive is excluded, evolving 143, 37.5, and 102 J g−1 for PVDF/CB, PEDOT:PSS, and PEDOT:PSS/CB composite binders, respectively. Additionally, conducting binders provide enhanced stability against LiXC6, generating less than 16% of the 728 J g−1 from the PVDF/CB graphite anode. In full-cell thermal safety studies with LiCoO2 (LCO) cathode using multimode calorimetry (MMC), this reduces heat generation at temperatures (<140 °C) where thermal runaway may still be circumvented. Electrochemical performance is not sacrificed as PEDOT:PSS/CB provides improved capacity (400 vs. 360 mAh g−1 after 100 cycles at C/5) and kinetics (260 and 189 mAh g−1 at 1C) over PVDF/CB.