Defect Engineered Dendritic Fibrous Nanosilica as Prospective Alloy Anode for the Fabrication of High-Energy Li-Ion Capacitors with Ultralong Durability

Lithium-ion capacitors (LICs) are the next generation electrochemical energy storage devices with two different types of energy storage mechanisms, anode and cathode. The LICs are anticipated to bridge the gap between lithium-ion batteries and supercapacitors by providing higher energy and power density than the individual charge storage systems. Our work reports the synthesis of defect-engineered dendritic fibrous nanosilica (SiOx) as an anode and commercial activated carbon (AC) as a cathode for the LICs. The Li/SiOx is prelithiated (LixSi + Li2O) prior to the fabrication of the LIC for a few cycles and is then paired with the mass-balanced AC electrode to get AC/(LixSi + Li2O)-based LIC assembly. Our LIC displays an excellent electrochemical performance with a maximum energy density of 169.7 Wh kg-1 at room temperature with ultralong durability of >48 000 cycles. The possibility of exploring LIC at different climatic conditions is also analyzed at various temperatures from -5 to 50 degrees C.