Upcycling Graphite from Spent Li-Ion Battery with SiO_x via Mechano-Chemical Process as Next-Generation Anode for...

Hybrid supercapacitors such as Lithium-ion capacitors (LICs) are one of the most modern energy storage devices of great research interest. The hybridization of the battery-type anode with the capacitive-type cathode brings out the synergic effect of enhanced energy density, power capability, long cycle life, and wide operating temperature. Herein, we introduce a simultaneous alloying-intercalation process from the recovered graphite: silicon monoxide (RG: SiO_x) composite as a negative electrode for the LIC applications with the activated carbon (AC) as a counter electrode. The RG from spent lithium-ion batteries is mixed with commercially available SiO_x by scalable mechano-chemical process, i. e., planetary ball-milling, to obtain a high-performance composite with various ratios. The LIC is assembled with an electrochemically prelithiated anode (Li_xSi + LiC₆ + Li₂O) and paired with AC under balanced mass loading conditions. The LIC delivered a maximum energy density of 218 Wh kg^-1 and power density of 8.45 kW kg^-1 with an ultra-long cycling life of over 20,000 cycles. Remarkably, the energy densities such as 208.7 and 201.4 Wh kg^-1 are observed at various temperature conditions like 10 and 40 °C, respectively, with excellent capacity retention characteristics.