1. Lithium foil replenishment
Lithium foil replenishment is a technique that utilizes the self-discharge mechanism to replenish lithium. Metallic lithium has the lowest potential among all electrode materials. Due to the potential difference, when the negative electrode material comes into contact with the metallic lithium foil, electrons spontaneously move towards the negative electrode, accompanied by the insertion of Li+ ions into the negative electrode.
2. Stabilized Lithium Metal Powder (SLMP)
Compared to adding it during the slurry mixing process, directly loading SLMP onto the dry anode surface is simpler and easier. Pre-lithiation of silicon-carbon nanotube anodes using SLMP involved dropping a 3% (w/w) SLMP/toluene solution onto the silicon-carbon nanotube anode surface. After the toluene solvent evaporated, the anode was pressed into a tablet and activated. After pre-lithiation, the initial irreversible capacity of the anode decreased by 20%–40%.
3. Lithium silicide powder
The small size of the nano-lithium silicide powder makes it easier to disperse in the negative electrode; in addition, it is already in an expanded state, and the volume change during cycling will not affect the structure of the entire electrode.
4. Lithium replenishment via electrolysis of lithium salt aqueous solution.
Lithium replenishment of silicon is achieved by electrolyzing an aqueous solution of Li₂SO₄ in an electrolytic cell. The sacrificial electrode is a copper wire immersed in Li₂SO₄. Regardless of whether lithium foil, SLMP, or lithium silicide powder is used for lithium replenishment, the use of metallic lithium is always involved. Metallic lithium is expensive, highly reactive, difficult to handle, and requires significant costs for storage and transportation.
With the deepening of research on lithium-ion battery materials, the improvement of manufacturing levels, and the increasing market demands for battery performance, the traditional approach of simply replacing electrode materials and developing new electrolytes to improve lithium-ion battery performance has become very limited. The emergence of pre-lithiation technology provides an effective solution for improving lithium-ion battery performance, particularly in mitigating irreversible capacity loss and increasing energy density, injecting new vitality into the development of lithium-ion battery technology.
