Diffusion Kinetics Study of Lithium Ion in the Graphdiyne Based Electrode

Herein,we report a comparative investigation of the electrochemical lithium diffusion within graphidyne(GDY)based electrodes.The transfer kinetic behaviors of lithium ions during the insertion/extraction process are analyzed through different methods including the galvanostatic intermittent titration technique(GITT)and the electrochemical impedance spectroscopy(EIS).GDY with the morphology of nanosheets(GDY NS)shows lithium diffusion coefficients in the orders range of 10-12-10-13 cm2/s through the GITT method.Meanwhile,EIS indicates quite a lower value of lithium diffusion coefficients between 10-13 and 10-15 cm2/s,which indicates that the analysis technique has an influence on the evaluation of GDY-based electrodes.In addition,under the same measurement condition of GITT,GDY nanoparticles(GDY NP)exhibit a lower value of Li+diffusion coefficient(10-14-10-16 cm2/s)during the charge-discharge process compared to those of GDY NS,which can be ascribed to the wide distributing range of particle size in GDY NP based electrodes.The analysis results in this work reveal that the aggregating forms of GDY electrode material have an important effect on the diffusion process of lithium ions,which provides a pathway to optimize the performance of GDY-based energy storage devices.