LAUSR

Abstract It is important to appraise the evolution of mechanical properties of current collectors and the adhesive strength of electrodes to reveal the chemical-mechanical coupling failure mechanism of lithium-ion batteries (LIBs), and to improve their cycling performance and cycling life. In this work, the mechanical properties of copper foil, anode, and cathode of commercial LIBs were studied under different cycling conditions by means of tensions with the aid of non-contact digital image correlation technique. It is found that different electrochemical cycle times and C-rates have great influence on the degradation of the mechanical properties of copper foil and the interfaces of graphite/copper foil and LiCoO2/alumina foil. The changes in elastic modulus, fracture strength and elongation of the copper foil were analyzed at 0.5C, 0.8C and 1.0C within 200 cycles, respectively. The adhesive strength of graphite/copper foil changes from its initial value 285.6 kPa to 55.5 kPa after 200 cycles at 1.0C, and the adhesive strength of LiCoO2/alumina foil decreases from its initial value 841.2 kPa to 132.8 kPa after 200 cycles at 1.0C.