Improving the electrochemical properties of LTO/rGO nanocomposite using PVDF:PMMA as a binary composite binder in Li-ion batteries

Polyvinylidene fluorinde (PVDF) is the main binder of Li-ion batteries (LIBs). Because of its drawbacks; however, great efforts have been made to enhance its properties, which, in turn, positively affect the electrochemical behavior of LIBs. In this regard, a nanocomposite based on spinel lithium titanate oxide and graphene oxide was synthesized via a thermal decomposition reduction method. For the first time, PVDF:PMMA with different weight ratios (x:4-x wt%, 0 ≤ x ≤ 4) was used as the composite binder for preparing LTO/rGO5wt% electrodes. The electrochemical performance of the electrodes was assessed by charge/discharge techniques, rate ability, cyclability, electrochemical impedance spectroscopy (EIS). The cyclic durability of the electrodes before and after charge-discharge cycles was examined by scanning electron microscopy (SEM). The LTO/rGO5wt% electrode with a PVDF:PMMA ratio of 2:2, i.e. the optimal sample, showed the highest electrochemical performance. The initial discharge capacity of the optimal sample at a 1C was 181.79 mAhg−1. In particular, according to the EIS results, a significant reduction in its charge transfer resistance and a significant increase in its lithium ion diffusion were observed.