The lithium-ion battery (LIB) industry has been in high demand for simple and effective methods to improve the electrochemical performance of LIBs. Here, we treated three different widely studied anode electrodes (i.e., Li4Ti5O12, TiO2, and graphite) under vacuum at 250 °C, and compared their electrochemical performance with and without a 250 °C treatment. Without changing the composition of the fabricated electrodes, all of the 250 °C treated electrodes exhibited enhanced specific capacities, and the lithium-ion diffusion was improved in different degrees. By comparing the results of scanning electron microscopy (SEM) and energy-dispersive spectroscopy of the pristine and 250 °C treated electrodes, the 250 °C treatment improved the distribution of a polyvinylidene difluoride (PVDF) binder in the electrodes, resulting in a higher porosity of the 250 °C treated electrodes. The results of X-ray photoelectron spectrometry and SEM of the cycled electrodes confirmed that a uniform distribution of the PVDF binder from the 250 °C treatment played a positive role in the formation of a solid electrolyte interphase layer, thereby delivering higher capacities and capacity retentions than those of electrodes without heat treatment. The simplicity of this modification method provides considerable potential for building high-performance LIBs at a larger scale.
Keywords: PVDF binder; anode; heat treatment; lithium-ion battery; solid electrolyte interphase.