Film electrode Li1-xMn2O4/C/PAA-c-CMCLi-b-PVDF by double cross-linking for selective extraction of Li+

Abstract

Because of its excellent stabilities, polyvinylidene fluoride (PVDF) is commonly employed as a binder in electrode fabrication. However, poor adhesion and hydrophilicity limit its applicability. Herein, PVDF as the hydrophobic framework, polyacrylic acid (PAA), and carboxymethylcellulose lithium (CMCLi) composite binders were cross-linked with phytic acid and Li1-xMn2O4/C were used in the formulation. After 100 electrochemical cycles, the film electrode Li1-xMn2O4/C/PAA-c-CMCLi-b-PVDF exhibits excellent adhesion (0.93 N cm−1) and a low capacity fading rate (8.2 %). Furthermore, this film electrode demonstrated a high intercalation capacity (32.14 mg g−1), a short intercalation equilibrium time (within 2 h), and a fast Li+ intercalation rate, which can be attributed to the synergistic effect of electrolyte permeability enhanced by hydrophilic functional groups (–OH and –COOH), dispersibility of electrode material particles improved by high slurry rheology, and the high transport efficiency of –COOH for Li+. These promising results suggest that this double cross-linked Li1-xMn2O4/C/PAA-c-CMCLi-b-PVDF film electrode is suitable for the selective extraction of Li+.