Performance study of new aqueous binder carboxymethyl cellulose ammonia (CMC-NH4) binder for graphite anode

Carboxymethyl cellulose ammonium (CMC-NH₄) is cellulose by etherification reaction and dehydration of glucose on the base unit (anhydrous glucose units, AGU) hydroxy was replaced by the carboxymethyl groups partially or completely, thus forming a kind of carboxymethyl cellulose ether derivatives. In this paper, the effect of CMC-NH₄ as a binder on graphite anode was investigated. Compared with CMC-Na binder, CMC-NH₄ as binder showed more excellent bonding properties as well as electrochemical properties. At 0.5C, the capacity retention of Gr-CMC-NH₄ after 500 cycles was improved by 15.3% compared to CMC-Na, and its capacity retention remained 81.5% after cycling. Further, the influence mechanism of different binders on the cycling performance of graphite electrodes was investigated by testing the first charge/discharge curves, cyclic voltammetry curves, electrochemical impedance before and after cycling, and analyzing the electrode SEM before and after cycling. It was found that CMC-NH₄ was able to inhibit the decomposition of the electrolyte, thus enhancing the multiplicity performance. The stabilization of the excellent long cycling performance is attributed to the fact that CMC-NH₄ can always provide excellent binder performance during the long cycling process to ensure the structural integrity of the electrode. Through the slurry stability test, the suspension and dispersion properties of the two binders were compared at 4, 8, 16, and 48 hours, respectively, and similar suspension and dispersion abilities were found, indicating that CMC-NH₄ can be used as a graphite anode binder.In summary, this study shows that compared with CMC-Na binder, CMC-NH₄ as a binder in graphite negative electrode exhibits superior bonding and electrochemical properties, and has potential application prospects.