Eco-friendly Aqueous Binder-Based LiNi 0.4 Mn 1.6 O 4 Cathode Enabling Stable Cycling Performance of High Voltage Lithium-Ion Batteries with Biomass-Derived Silica

High voltage cathode materials LiNi x Mn 2−x O 4 (x = 0.4; 0.5) have been attracting greater attention in developing high energy density Li-ion battery technology for electrical vehicles and large-scale applications. The main challenge of high voltage cathodes is severe electrolyte decomposition leading to short cell cycle life. In addition, LiNi 0.4 Mn 1.6 O 4 cathode material processed with polyvinylidene fluoride (PVdF) binder generally suffers an oxidation decomposition as well as cathode delamination 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 demonstrate the effectiveness 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 than the one using PVdF binder (CMC—126.0 mAh/g; LiPAA—125.7 mAh/g; PVdF—117 mAh/g at C/5, respectively). CMC and LiPAA also improve retention capacity up to 90% after 500 cycles at C/3. Interestingly, LiPAA based electrode exhibits an excellent rate-capability with discharge capacity of 80 mAh/g at 8C. The stability of electrodes was also investigated by electrode chemical impedance spectroscopy (EIS) and Scanning electron microscope (SEM). In full-cell, CMC and LiPAA based cells showed effectiveness in decreasing transition metal dissolution and preventing the cathode degradation during long-cycling through its excellent capacity retention in 200 cycles at C/3. Graphical Abstract