A positive-temperature-coefficient electrode with thermal cut-off mechanism for use in rechargeable lithium batteries

Abstract A novel positive-temperature-coefficient (PTC) electrode was prepared by coating a thin layer of epoxy-carbon PTC material in between the electroactive LiCoO2 layer and the electrode substrate and used for self-actuating thermal cut-off of Li-ion batteries when the batteries are overheated. Experimental results from cyclic voltammetry, impedance spectrometry and charge–discharge measurements demonstrate that the PTC electrode exhibits normal electrochemical behaviors at ambient temperature, but shows an enormous increase in the resistance at the temperature range of 100–130 °C. This PTC behavior of the electrode provides a current-limiting effect, acting as a reversible thermal shutdown switch for rechargeable lithium batteries.