Application： This product offered here allows an ambient-air-tolerant method for negative electrode prelithiation prior to assembly of Li ion batteries. The redox potential of this product makes it useful for those most reported negative electrodes including Si with high capacities and short processing time. It could not only compensate for the initial active lithium loss, but also enable the pairing with high-capacity lithium-free positive electrodes (e.g. sulfur, oxygen, V2O5 etc.) that requires the supply of Li source from the negative electrode to configure Li ion batteries with high energy densities