A Water‐Soluble NaCMC/NaPAA Binder for Exceptional Improvement of Sodium‐Ion Batteries with an SnO₂‐Ordered Mesoporous Carbon Anode

Abstract

SnO2@CMK‐8 composite, a highly promising anode for Na‐ion batteries (NIBs), was incorporated with polyvinylidene difluoride (PVDF), sodium carboxymethylcellulose (NaCMC), sodium polyacrylate (NaPAA), and NaCMC/NaPAA mixed binders to optimize the electrode sodiation/desodiation properties. Synergistic effects between NaCMC and NaPAA led to the formation of an effective protective film on the electrode. This coating layer not only increased the charge–discharge Coulombic efficiency, suppressing the accumulation of solid–electrolyte interphases, but also kept the SnO2 nanoparticles in the CMK‐8 matrix, preventing the agglomeration and removal of oxide upon cycling. The adhesion strength and stability towards the electrolyte of the binders were evaluated. In addition, the charge–transfer resistance and apparent Na+ diffusion of the SnO2@CMK‐8 electrodes with various binders were examined and post‐mortem analyses were conducted. With NaCMC/NaPAA binder, exceptional electrode capacities of 850 and 425 mAh g−1 were obtained at charge–discharge rates of 20 and 2000 mA g−1, respectively. After 300 cycles, 90 % capacity retention was achieved. The thermal reactivity of the sodiated electrodes was studied by using differential scanning calorimetry. The binder effects on NIB safety, in terms of thermal runaway, are discussed.

High-performance sodium-ion batteries with a hard carbon anode: transition from the half-cell to full-cell perspective

“…FEC and other additives must be reconsidered for their compatibility with the hard carbon anode in well matched full-cell SIBs. Meanwhile, it is worth mentioning that the binder can assist in forming a protective layer on the electrode and reducing the continuous growth of SEI, 65 which was usually overlooked in previous studies.…”

Conversion‐Alloying Anode Materials for Sodium Ion Batteries

“…reported a water soluble NaCMC (sodium carboxymethylcellulose)/NaPAA(sodium polyacrylate) binder to optimize the sodiation/de‐sodiation properties of SnO 2 . [ 136 ] In this work, the synergistic effects that a usefully protective layer was formed on the electrode surface resulted from the mixed binders of NaCMC and NaPAA were proven. This protective film not only improved the CE by inhibiting the growth of SEI, but also suppressed the agglomeration and removal of SnO 2 during cycling.…”

“…Reproduced with permission. [ 136 ] Copyright 2018, Wiley‐VCH. f–h) Effects of temperature on reversible capacity at 20 mA g −1 , capacity retained ratios at 1000 mA g −1 (compared to values at 20 mA g −1 ), and cyclic stability of SnO 2 /graphene electrodes measured in PC/EC/FEC and PMP–FSI IL electrolytes.…”

“…e) Rate capability of the C/SnO 2 /C electrode. Reproduced with permission [136]. Copyright 2018, Wiley-VCH.…”

Effect of new crystalline phase on the ionic conduction properties of sodium perchlorate salt doped carboxymethyl cellulose biopolymer electrolyte films

“…NaCMC is a semi-synthetic derivative of cellulose, and the presence of sodium carboxymethyl group (CH 2 COONa) makes it highly soluble in water and also act as a polyelectrolyte [7]. NaCMC also has emerged as a promising inexpensive alternative binder for the active electrode material particles over conventional high cost, non-environmentally friendly binder, polyvinylidene difluoride (PVDF) for lithium-ion and sodium-ion batteries with improved performance [8][9][10]. While selecting a polymer as a matrix, it should satisfy specific criteria; it should be amorphous in nature with high solvation power with coordination sites to assist ion-pair dissociation.…”