White Latex: Appealing "Green" Alternative for PVdF in Electrode Manufacturing for Sustainable Li-Ion Batteries.

Abstract

Nowadays, poly(vinylidene fluoride) (PVdF) has been dominantly utilized as a polymeric binder in commercialized Li-ion batteries. However, standardized PVdF-based electrode manufacturing seems cost-intensive and environmentally hazardous, which relies on the usage of toxic N-methyl-2-pyrrolidone (NMP) as a dispersant. In view of cost control and environmental awareness, switching to a water-processable green binder, as a substitute for PVdF, has been imperative with realistic significance. Herein, commercially available white latex (WL), containing poly(vinyl acetate) as a staple ingredient, was directly used as an alternative aqueous binder for PVdF in the fabrication of graphite/Li4Ti5O12-based lithium-ion anodes. WL exhibits robust adhesion of the electrode coating to the current collector; meanwhile, the restricted electrolyte swelling of the binder is verified by in situ electrochemical dilatometry. Outperforming PVdF, WL endows graphite with extensive surface coverage by the binding agent, dramatically reducing irreversible decomposition of the electrolyte (SEI formation) on graphite. Consequently, the WL-based graphite anode delivers the highest initial coulombic efficiency (CE) of 92% and remarkable long cyclic stability with a high capacity retention of 332.7 mAh/g, compared to the PVdF- and carboxymethyl cellulose (CMC)-based ones. Moreover, WL is also compatible with Li4Ti5O12, endowing it with more stable cycling behavior than that of the counterparts prepared with both PVdF and even CMC. Our described WL represents an appealing "green" alternative for PVdF in manufacturing sustainable and ecofriendly energy storage devices.