Advanced Sustainable Trilayer Cellulosic “Paper Separator” Functionalized with Nano-BaTiO<sub>3</sub> for Applications in Li-Ion Batteries and Supercapacitors
Mononita Das, Pradip Sekhar Das, Nimai Chand Pramanik, Rajendra N. Basu, Mir Wasim Raja
Abstract
High Resolution Image Download MS PowerPoint Slide In the quest of developing a sustainable, low-cost and improved separator membrane for application in energy storage devices like lithium-ion batteries (LIBs) and supercapacitors (SCs), here we fabricated a trilayer cellulose-based paper separator engineered with nano-BaTiO 3 powder. A scalable fabrication process of the paper separator was designed step-by-step by sizing with poly(vinylidene fluoride) (PVDF), thereafter impregnating nano-BaTiO 3 in the interlayer using water-soluble styrene butadiene rubber (SBR) as the binder and finally laminating the ceramic layer with a low-concentration SBR solution. The fabricated separators showed excellent electrolyte wettability (216–270%), quicker electrolyte saturation, increased mechanical strength (43.96–50.15 MPa), and zero-dimensional shrinkage up to 200 °C. The electrochemical cell comprising graphite|paper separator|LiFePO 4 showed comparable electrochemical performances in terms of capacity retention at different current densities (0.05–0.8 mA/cm 2 ) and long-term cycleability (300 cycles) with coulombic efficiency >96%. The in-cell chemical stability as tested for 8 weeks revealed a nominal change in bulk resistivity with no significant morphological changes. The vertical burning test as performed on a paper separator showed excellent flame-retardant property, a required safety feature for separator materials. To examine the multidevice compatibility, the paper separator was tested in supercapacitors, delivering a comparable performance to that of a commercial separator. The developed paper separator was also found to be compatible with most of the commercial cathode materials such as LiFePO 4, LiMn 2 O 4, and NCM111.