Green aqueous binder poly(N-vinylformamide) for high-rate capability Li4Ti5O12 anode in lithium-ion batteries

Abstract

To persue sustainable developments, poly (N-vinylformamide) (PNVF) is investigated as a green, bio-derived and water-soluble binder for Li4Ti5O12 (LTO) anode in lithium-ion batteries (LIBs). Electrochemical performance differences between PNVF electrodes and the conventional polyvinylidene fluoride (PVDF) electrodes are presented. The electrodes are characterized by peeling test, the galvanostatic charge/discharge cycle test, electrochemical impedance analysis (EIS), cyclic voltammetry (CV) and scanning electron microscope (SEM). The electrode with 3 wt% PNVF shows higher peeling force than the one with 10 wt% PVDF. The electrodes with 3 wt% PNVF and 10 wt% PVDF exhibit similar rate capability, whereas the capacity retention at 1C-rate is 91.2% (144 mAh/g) and 76.1% (123 mAh/g) after 1000 cycles, respectively. EIS and CV results exhibit that the lithium-titanium oxide (LTO) electrode with optimal PNVF binder (3 wt%) shows lower RSEI and Rct values as compared to that with PVDF counterpart and optimal PNVF electrode exhibits high lithium-ion diffusion coefficient. To enhance the cyclability and high-rate performance, vinylene carbonate (VC) is added as an electrolyte additive afterwards, and the results improve accordingly. Therefore, the results present in this paper demonstrated that PNVF is a potential aqueous binder for LTO anode within green fabrication.