Artificial SEI for Superhigh-Performance K-Graphite Anode.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Graphite is a low-cost, abundant anode material for potassium ion batteries (PIBs).
• However, graphite anodes suffer from poor cycle life due to solid electrolyte interface (SEI) decomposition in organic electrolytes.
• Developing a stable SEI is crucial for high-performance PIBs.

Purpose of the Study:

• To create a stable artificial inorganic SEI film on commercial graphite anodes.
• To improve the cycle stability and initial Coulombic efficiency (ICE) of PIBs using traditional carbonate electrolytes.
• To enable the commercial viability of PIBs.

Main Methods:

• A simple and viable method was used to prepare an ultra-thin, uniform, dense, and stable artificial inorganic SEI film.
• Commercial graphite anodes coated with the SEI film were tested in traditional carbonate electrolytes.
• Electrochemical performance, including cycling stability and ICE, was evaluated.

Main Results:

• The modified graphite anodes demonstrated long-term cycling stability exceeding 1000 cycles at 100 mA g⁻¹ with a reversible capacity of ~260 mAh g⁻¹.
• A high average Coulombic efficiency (CE) of ~99.9% was achieved with no discernible capacity decay.
• The anodes exhibited a record-high ICE of 93% in traditional carbonate electrolytes.

Conclusions:

• The artificial inorganic SEI film effectively prevents SEI decomposition, enhancing graphite anode performance in PIBs.
• This method offers a pathway to long-cycle stability and high ICE for PIBs.
• The findings support the commercialization of potassium ion batteries.