An Aqueous Binder for High-Areal-Capacity Fe₃O₄-Based Anodes in Lithium-Ion Batteries

Binders have an important effect on improving the electrochemical performance of lithium-ion batteries, but binders are yet to receive much attention in Fe3O4-based electrodes. Herein, polyacrylamide (PAM) is developed as an aqueous binder for high-capacity carbon-coated Fe3O4 (Fe3O4@C-PAM) anodes. Benefitting from its strong adhesion strength and robust mechanical properties, PAM as a binder, besides effectively tolerating the huge volume changes of Fe3O4, keeps the integrity of the Fe3O4-based electrode during cycling. In addition, compared with a polyvinylidene difluoride (PVDF) binder, the water-soluble PAM binder enables the fabrication of Fe3O4-based electrodes in a green and low-cost process. These appealing characteristics lead to better electrochemical performances of Fe3O4@C-PAM anodes than those of Fe3O4@C-PVDF anodes. Moreover, the PAM binder is effective for high Fe3O4@C loading electrode (6.8 mg cm–2), enabling a high areal capacity of 8.06 mA h cm–2.