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

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-ion capacitors (LICs) require efficient anode materials for enhanced performance.
• Vanadium pentoxide (V₂O₅) is a potential candidate, but its electrochemical properties need optimization.
• Developing advanced electrode materials is crucial for next-generation energy storage devices.

Purpose of the Study:

• To investigate the feasibility of using electrochemically generated γ-LiₓV₂O₅ as an insertion-type anode in LICs.
• To evaluate the performance of LICs with γ-LiₓV₂O₅ anodes and activated carbon (AC) cathodes.
• To explore the impact of electrolyte modification on the energy density and performance of these LICs.

Main Methods:

• Synthesis of γ-LiₓV₂O₅ via electrochemical pre-lithiation.
• Preparation of V₂O₅ carbon composites using high-energy ball milling.
• Fabrication of LICs using γ-LiₓV₂O₅ anodes and AC cathodes in an organic electrolyte.
• Electrolyte modification using fluoroethylene carbonate (FEC).
• Electrochemical characterization including energy density and capacity retention measurements.

Main Results:

• The AC/γ-LiₓV₂O₅-BM50 configuration achieved an energy density of 33.91 Wh kg⁻¹ at 0.22 kW kg⁻¹ with good capacity retention.
• Electrolyte modification with FEC significantly increased the energy density to 43.98 Wh kg⁻¹ at 0.28 kW kg⁻¹.
• The γ-LiₓV₂O₅ phase demonstrated potential for high-temperature performance in hybrid charge storage devices.

Conclusions:

• Electrolytically generated γ-LiₓV₂O₅ is a viable anode material for lithium-ion capacitors.
• Fluoroethylene carbonate electrolyte modification enhances the energy density of AC/γ-LiₓV₂O₅ based LICs.
• γ-LiₓV₂O₅ shows promise as a battery-type component for high-performance hybrid energy storage systems.