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 (SiO x ) as an anode and commercial activated carbon (AC) as a cathode for the LICs. The Li/SiO x is prelithiated (Li x Si + Li 2 O) prior to the fabrication of the LIC for a few cycles and is then paired with the mass-balanced AC electrode to get AC/(Li x Si + Li 2 O)-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 °C.