With the rapid development of mobile electronic products, large-scale energy storage and electric vehicles, the development of lithium-ion and post-lithium-ion batteries with high energy density, high power density, long cycle life, and high safety has become a research hotspot and focus in the field of energy storage . The development of electrode materials with high capacity, high rate and high stability is an important way to achieve this goal.
In recent years, the team of Li Xianglong and Zhilinjie of the National Nanoscience Center started from low-cost silica nanoparticles, improved the magnesium thermal reduction technology, and prepared a hydrangea-like silylene material on a large scale, which was demonstrated when applied to lithium-ion batteries. Outstanding comprehensive lithium storage performance. Recently, the research team proposed and developed a "skin-like" two-dimensional covalent packaging strategy, based on the hydrangea-like silylene to further prepare the silico-oxygen-carbon bond-based hydrangea-like covalent diene, showing a good comprehensive lithium storage performance: The weight-to-volume specific capacity at a current density of 800 mA/g is as high as 2646 mAh/g and 2350 mAh/cm3, respectively, and the weight-to-volume specific capacity remains nearly 1500 mAh/g after 500 cycles at a current density of 2000 mA/g; At a current density of 20000 mA/g, the specific capacity by weight is still as high as 810 mAh/g, and the specific capacity by volume is 1358% and 1442% higher than that of non-covalent packaging and unencapsulated materials, respectively; based on the overall device calculation, based on the carbon silicon The full battery energy density of the material is 40% to 60% higher than that of graphite-based batteries, and the specific energy and energy density of current commercial lithium-ion batteries are both higher than 40%. Preliminary studies have shown that the two-dimensional covalent packaging strategy not only provides an efficient mixed transmission channel for electrons/lithium ions, but also changes the material interface to ensure efficient and stable transmission of electrons/lithium ions while effectively alleviating the volume expansion of silicon.
Related results were published on "Nature-Communication" with the title of Stable high-capacity and high-rate silicon-based lithium battery anodes upon two-dimensional covalent encapsulation. The research was supported by the National Natural Science Foundation of China and the Youth Promotion Association of the Chinese Academy of Sciences.
Skin grafting two-dimensional covalent packaging strategy, high comprehensive performance carbon silicon anode construction and lithium storage performance
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