High voltage cathode materials LiNi x Mn 2−x O 4 (x = 0.4; 0.5) have been attracting greater attention in developing high energydensity Li-ion battery technology for electrical vehicles and large-scale applications. The main challenge of high voltag...
High voltage cathode materials LiNi x Mn 2−x O 4 (x = 0.4; 0.5) have been attracting greater attention in developing high energydensity Li-ion battery technology for electrical vehicles and large-scale applications. The main challenge of high voltagecathodes is severe electrolyte decomposition leading to short cell cycle life. In addition, LiNi 0.4 Mn 1.6 O 4 cathode materialprocessed with polyvinylidene fl uoride (PVdF) binder generally suff ers an oxidation decomposition as well as cathodedelamination from current collectors during cycling. Herein, we suggest using sodium carboxymethyl cellulose (CMC),lithium polyacrylic acid (LiPAA) as water-soluble binders for replacing conventional PVdF in cathode processing to demonstratethe eff ectiveness on long-cycling of half-cell Li || LiNi 0.4 Mn 1.6 O 4 , full-cell SiO 2 -graphite || LiNi 0.4 Mn 1.6 O 4 and SiO 2|| LiNi 0.4 Mn 1.6 O 4 . In half-cell, the cells with water-soluble binders-based cathode exhibited a higher discharge capacity thanthe one using PVdF binder (CMC—126.0 mAh/g; LiPAA—125.7 mAh/g; PVdF—117 mAh/g at C/5, respectively). CMCand LiPAA also improve retention capacity up to 90% after 500 cycles at C/3. Interestingly, LiPAA based electrode exhibitsan excellent rate-capability with discharge capacity of 80 mAh/g at 8C. The stability of electrodes was also investigated byelectrode chemical impedance spectroscopy (EIS) and Scanning electron microscope (SEM). In full-cell, CMC and LiPAAbased cells showed eff ectiveness in decreasing transition metal dissolution and preventing the cathode degradation duringlong-cycling through its excellent capacity retention in 200 cycles at C/3.