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

Abstract

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 + 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/(Li x Si + 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 °C.

High-performance Si@C anode for lithium-ion batteries enabled by a novel structuring strategy

“…40 During the first anodic scanning process, it shows two peaks at ∼0.37 and ∼0.53 V, corresponding to the delithiation of amorphous Li x Si (∼0.37) and crystalline Li 15 Si 4 (∼0.53 V) to form amorphous Si. 41,42 From the second cycle, the cathodic scanning branch displays a broad peak at ∼0.17 V and a sharp peak at ∼0.01 V, related to the lithiation of Si to Li x Si alloys and transition of highly lithiated amorphous-Li x Si into crystalline-Li 15 Si 4 phase (including lithium insertion of carbon matrix), respectively. 39,41 The potentials of the anodic peaks for the delithiation process are almost consistent with that in the first cycle.…”