(Original title: Chinese and American scientists have developed fast-charging lithium-ion battery materials)

IT House News on October 9 learned from the University of Science and Technology of China that the Hefei National Research Center for Microscale Matter Science, Chinese University of Science and Technology of China, and Professor Ji Hingxing from the Key Laboratory of Energy Conversion Materials of the Chinese Academy of Sciences, School of Chemistry and Materials Science, and Duan Xiangfeng, University of California, Los Angeles Professors have made important progress in the field of lithium-ion batteries.

IT Home learned that the research results were titled "Black Phosphorus Composites with Engineered Interfaces for High-Rate High-Capacity Lithium Storage" and were published in the internationally renowned academic journal "Science 2020, 370" on October 9, 2020. , 192–197).

According to the University of Science and Technology of China, one of the keys to determining the power density of lithium-ion batteries is the rate performance of the negative electrode material. The research of Jixingxing’s research group in recent years found that black phosphorus has extremely high mass capacity when used as the anode of alkali metal ion batteries (Angew. Chem. Int. Ed. 2020,59, 2318; ACS Appl. Mater. Inter.2019,11 , 16656), and the layered structure and semiconductor properties of black phosphorus also indicate that black phosphorus should have extremely high rate performance. However, in-depth research has found that black phosphorus is prone to structural damage starting from the edge of the two-dimensional sheet (J. Am. Chem. Soc. 2018,140, 7561). The boundary structure of black phosphorus can be stabilized by chemical modification and accompanied by related physics. The reproduction of properties (Angew. Chem. Int. Ed. 2019, 58, 1479; Adv. Mater. 2017, 29, 1605776). Inspired by these research results, Ji Xingxing and others used high-energy ball milling to obtain a composite material in which black phosphorus nanosheets and graphite nanosheets are arranged side by side and connected by carbon-phosphorus covalent bonds, which enables lithium ions to efficiently shuttle in the composite material. ; Further optimize the solid electrolyte interface membrane by polyaniline coating, so that lithium ions can quickly enter the composite material.

▲ Black phosphorus composite anode material structure and lithium storage performance. Source: University of Science and Technology of China

According to reports, the composite material can achieve a reversible mass capacity of nearly 500 mAh/g (composite material) at a current density of 13 A/g under the condition of a compaction density of 1.49 g/cm-3, and stable cycles up to 2000 times . The test results of electrochemical in-situ X-ray absorption spectroscopy and time-of-flight secondary ion mass spectrometry respectively show that the formation of carbon-phosphorus covalent bonds is the key to improving the electrochemical reaction of black phosphorus; polyaniline is enriched by the swelling of the electrolyte solvent The solid electrolyte interface membrane of organic components is the key to improving the ability of lithium ions to enter composite particles.

Source: IT House, translated by Google Translate