A High-Voltage, Dendrite-Free, and Durable Zn-Graphite Battery

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable zinc batteries offer intrinsic advantages like high capacity and safety.
• Current limitations include low cell voltage (<2 V) due to electrolyte and cathode constraints.
• Zinc anode dendrite formation and poor rechargeability hinder long-term performance.

Purpose of the Study:

• To develop a high-voltage and durable zinc-graphite battery system.
• To overcome the limitations of low voltage and poor cyclability in conventional zinc batteries.
• To enable stable and efficient operation of zinc-graphite batteries at elevated voltages.

Main Methods:

• Development of a hybrid electrolyte containing lithium hexafluorophosphate (LiPF6).
• Electrochemical characterization to determine the electrochemical stability window (ESW).
• Cycling performance evaluation of the zinc-graphite battery under high charge-discharge rates.

Main Results:

• The LiPF6-containing hybrid electrolyte achieved a super-wide ESW of 4 V (vs Zn/Zn2+).
• Dendrite-free zinc plating/stripping and reversible dual-anion intercalation into graphite were observed.
• The zinc-graphite battery operated stably at 2.8 V with a 2.2 V midpoint discharge voltage.
• Exceptional cycling stability with 97.5% capacity retention after 2000 cycles and ≈100% Coulombic efficiency.

Conclusions:

• The developed hybrid electrolyte effectively suppresses zinc anode oxidation and expands the voltage window.
• The LiPF6-enabled system facilitates dendrite-free zinc deposition and reversible graphite intercalation.
• This high-voltage zinc-graphite battery demonstrates significant potential for long-term, high-performance energy storage.