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1.Research Background A major challenge in vanadium redox flow batteries is the competition between the main and side reactions of hydrogen evolution associated with the V(II)/V(III) redox couple at the negative electrode.

1. What is Lithium Deposition on the Negative   Electrode? The lithium intercalation potential of graphite is between 65–200 mV (vs. Li+/Li0). When the potential of the negative electrode approaches or drops below the deposition potential of metallic lithium, lithium ions will be deposited as metallic lithium on the surface of the negative electrode. Experiments have shown that during the charging process, some lithium ions are deposited as metallic lithium on the surface of the negative electrode, while the remaining lithium ions intercalate into the graphite or other negative electrode materials. During discharge, both ion de-intercalation and the stripping of deposited lithium metal occur simultaneously. In the process of lithium metal stripping, "dead lithium" is formed. In short, the phenomenon of lithium deposition on the negative electrode refers to the simultaneous intercalation and deposition of lithium ions during the charge and discharge processes, causing lithium ...

1. Research Abstract Combining high-voltage nickel-rich cathodes with lithium metal anodes is one of the most promising approaches to achieving high-energy-density lithium batteries. However, most current electrolytes cannot simultaneously meet the requirements for compatibility with lithium metal anodes and tolerance for ultra-high-voltage NCM811 cathodes. In this study, by adjusting the composition of fluorinated carbonate-based electrolytes, an ultra-anti-oxidative electrolyte was designed. The research found that through the synergistic decomposition of fluorinated solvents and PF6- anions, an SEI (solid electrolyte interphase) rich in LiF and Li2O was constructed on the lithium anode, which facilitated smooth deposition of lithium metal. More importantly, this electrolyte exhibited excellent antioxidant properties, enabling Li||NCM811 coin cells to maintain 80% of their capacity after 300 cycles at an ultra-high cut-off voltage of 4.8 V. Furthermore, under harsh conditions of high...

1.  Key Factors Influencing Formation: Mechanism Generation Process of SEI Membrane: l  Electrons are transferred from the current collector, through the conductive agent, to point A inside the graphite particles where the SEI membrane is to be formed. l  Solvated lithium ions, wrapped in the solvent, diffuse from the cathode to point B on the surface of the SEI membrane that is currently being formed. l  The electrons at point A diffuse to point B through the electron tunneling effect. l  The electrons that jump to point B react with lithium salt, solvated lithium ions, film-forming agents, etc., to continue generating the SEI membrane on the surface of the existing SEI membrane. This process results in the continuous increase of the SEI membrane thickness on the surface of the graphite particles, ultimately leading to the formation of a complete SEI membrane.

1.  Basic Concepts of Formation 1.1.  What is Formation? l  Formation refers to the process of activating the cathode and anode materials inside a battery after it has been fully rested following electrolyte injection. This activation is achieved through a specific charging and discharging cycle, which also leads to the formation of a SEI (Solid Electrolyte Interphase) film on the surface of the active materials. The SEI film helps to improve the overall performance of the battery in terms of charging and discharging, self-discharge, and storage capabilities.

  1. Coating Basics Purpose: To uniformly coat a fluid slurry onto the surface of a metal foil, dry it, and produce a battery electrode Principle: The coating roller rotates to carry the slurry, and the amount of slurry transferred is adjusted by adjusting the gap between the doctor blade and the roller. The relative rotation of the back roller and the coating roller is used to transfer the slurry onto the substrate. Subsequently, the solvent in the slurry is evaporated through drying and heating, causing the solid matter to adhere to the substrate.

  1. Electrode Shedding  Negative electrodes are prone to powder shedding  Main reason： 1. Formula issues,insufficient bonding strength leading to material loss 2.Excessive baking temperature,rapid solvent evaporation resulting in SBR bleeding.Insufficient adhesive between the material and the current collector leading to material loss