Electrochemically Generated γ-Lix V2 O5 as Insertion Host for High-Energy Li-Ion Capacitors

Abstract

In this study, we explored the feasibility of using electrochemically generated γ-Li_x V₂ O₅ as an insertion-type anode in the lithium-ion capacitor (LIC) with activated carbon (AC) as a cathode. Along with the native form of V₂ O₅ , their carbon composites are also used as the electrode material which is prepared by high-energy ball milling. The electrochemical pre-lithiation strategy is used to generate the desired γ-phase of V₂ O₅ (γ-Li_x V₂ O₅ ). Under the optimized mass loading conditions, the LICs are assembled with γ-Li_x V₂ O₅ as anode and AC as a cathode in the organic medium. Among the different LICs fabricated, AC/γ-Li_x V₂ O₅ -BM50 configuration delivered an energy density of 33.91 Wh kg^-1 @ 0.22 kW kg^-1 with excellent capacity retention characteristics. However, a dramatic increase in energy density (43.98 Wh kg^-1 @0.28 kW kg^-1 ) is noted after the electrolyte modification with fluoroethylene carbonate. The high temperature performance of the assembled LIC is also studied and found that γ-Li_x V₂ O₅ phase can be used as a potential battery-type component to construct high-performance hybrid charge storage devices.

Keywords: Li-ion capacitors; V2O5; energy density; high temperature; pre-lithiation.