Glyme solvated Na and Li-ion capacitors based on co-intercalation process using pencil graphite as battery type electrode

Co-intercalation, intercalation of solvated ions received significant research interest in the last decade mainly due to faster charge-discharge kinetics with enhanced diffusion and more excellent stability. Moreover, for the assembly of alkali metal-ion hybrid supercapacitors, with battery type anode and capacitive cathode, a co -intercalation-based anode is a suitable option to avoid the kinetic mismatch between the two electrodes and hence can guarantee better performance. In the present work, we considered pencil graphite (PG B), a cheap and readily available graphite silica composite, as a battery-type anode and commercial activated carbon (AC) as cathode for the assembly of glyme solvated Na and Li-ion capacitors ((PG B/1 M NaCF3SO3 in diglyme/AC) gs-NIC & ((PG B/1 M LiPF(6 )in tetraglyme/AC) gs-LIC). Such device prototypes could exhibit maximum energy -power storage capability of 78.7 Wh kg(- 1) and 3.73 kW kg(- 1) for gs-NIC and 47 Wh kg(- 1 )and 3.13 kW kg(- 1) for gs-LIC. Besides, the gs-NIC system with the minimum capacity and kinetic imbalance between the two elec-trodes displayed brilliant cyclic stability of > 97% capacity retention after 6000 charge-discharge cycles at a current density of 1 A g(-1). However, the co-intercalation electrolyte system (salt and solvent) plays a vital role in the device's overall performance.

Automated summary

Co-intercalation, an important research topic in the past decade, has shown enhanced charge-discharge kinetics, diffusion, and stability in solvated ion systems. In this study, pencil graphite and commercial activated carbon were used as anode and cathode, respectively, to assemble glyme solvated Na and Li-ion capacitors. The prototypes exhibited high energy-storage capability and power output.