Electroactive Polymer for Controlling Overcharge in Lithium-Ion Batteries

摘要

Lithium-ion cells placed in series are prone to overcharging, leading to shortened cycle life. The current method of control is expensive, yet ineffective, external control circuitry. We have addressed this problem by developing an alternative separator that reversibly becomes conductive when a cell reaches an overvoltage condition, shunting electrons between the electrodes at current densities up to 10 mA/cm~2. At cell operating voltages, the porous separator functions as a typical ion shuttle. For manufacturing concerns, the tensile yield strength of the durable film is 6.8 Mpa (normalizedforce to film width of 0.17 N/mm).