The invention of the graphite anode has greatly promoted the large-scale commercial application of lithium-ion batteries. The most important performance parameters of these batteries are charging speed, cycle life, and energy density. However, existing commercial graphite-based lithium-ion batteries are difficult to charge fast without sacrificing energy density, cycle life, and safety. This is because the slow electrochemical reaction process on the graphite negative surface limits the charging speed of the battery. This includes the desolvation of Li+ on the surface of the graphite negative solid electrolyte interface film (SEI) and the transport process of Li+ in the SEI. To improve the fast charge performance of lithium-ion batteries, it is important to explore new battery chemistry on the "old" graphite anode material, and it is expected to achieve rapid industrialization.

A recent study by the research group of Professor Sun Yongming, who is also the supervisor of ICARE at Wuhan Optoelectronics National Research Center, investigated the effects of various SEI components on Li+ desolvation. The study found that Li3P has a strong affinity for Li+ and can enhance the transport dynamics of Li+ at the negative electrode interface. Based on these results, the researchers created an ultra-thin P coating layer on graphite surface using the "bridging" effect of S to P, resulting in the formation of "blue" graphite. During the first battery cycle, a continuous crystalline Li3P-SEI with high ionic conductivity was formed in situ on the surface of the "blue" graphite. The "blue" graphite soft pack battery, which consists of LiNi0.6Co0.2Mn0.2O2 (NCM622) and "blue" graphite, demonstrated fast charging performance (91.2% and 80% of full charge in 10 minutes and 6 minutes, respectively) and satisfactory cycle performance under fast charging conditions (6C) (approximately 1 Ah, 2000 cycles, capacity retention rate of 82.9%). The researchers developed a 3 Ah battery and installed it in a mobile phone to power it. They were able to charge it for just 10 minutes and achieve a power level of 90.3%. This proves that "blue" graphite is an excellent material for fast-charging lithium battery negative electrodes. Due to its simple and convenient synthesis process, low raw material cost, and excellent electrochemical properties, "blue" graphite has great potential for practical use.

On October 30th, the research results were published online in Nature Energy under the article titled "Fast-Charging Capability of Graphite-Based Lithium-Ion Batteries Enabled by Li3P-Based Crystalline Solid-Electrolyte Interphase."