Amplify battery performance with black bezels grafted onto micron silicon

Silicon is the second most abundant element on earth, making up 27.7% of the earth’s crust. Besides its ability to create sand beaches and transparent glasses, silicon also has the potential to make highly efficient metal ion batteries.

In a world where alternative energy storage devices such as lithium-ion batteries are gaining traction, there is a need to exploit the excellent specific energy capacity of silicon as an electrode material. Commercial application of silicon-based electrode materials is often hampered for two main reasons: 1) lack of mechanical stability resulting from uncontrolled volume expansion during lithiation, the process of combining with a lithium-ion , and 2) the rapid energy fading caused by the formation of an unstable solid-electrode interface (SEI).

Over the years, scientists have developed various advanced silicon-based negative electrodes or anode materials to overcome the aforementioned problems. The most important of these are silicon nanomaterials. However, silicon nanomaterials have some drawbacks, such as a large gap between demand and supply, a difficult and expensive synthesis process, and most importantly, a threat of rapid battery drain.

Now, a group of researchers from the Japan Advanced Institute of Science and Technology (JAIST) led by Professor Noriyoshi Matsumi has come up with a solution to these problems plaguing silicon microparticles (SiMPs). In their published study in Journal of Materials Chemistry A July 18, 2022, the team presented a holistic approach to synthesize new highly resistant SiMPs made of silicon-grafted black (silicon oxycarbide) glasses as an anode material for lithium-ion batteries. The research team included Ravi Nandan, researcher, Noriyuki Takamori, PhD student, Koichi Higashimine, technical specialist, and Dr. Rajashekar Badam, former senior lecturer at JAIST.

“Silicon nanoparticles could provide increased effective surface area, but this has its own drawbacks, such as increased electrolyte consumption as well as low initial coulombic efficiency after a few charge and discharge cycles. SiMPs are the most suitable, least expensive, and most readily available alternatives, especially when combined with materials with exceptional structural properties, such as black silicon oxycarbide glasses. Our material is not only high performing, but also conducive to opportunities for scale,” Prof. Matsumi explained when asked about the rationale behind the study.

The team designed a core-shell type material where the core was made of SiMP coated with a carbon layer, then the black silicon oxycarbide glasses were grafted as the shell layer. The prepared materials were then used in an anode half-cell configuration to test their ability to reversibly store lithium under different potential windows. This screening showed that the material has high lithium diffusion capacity, reduced internal resistance and overall volumetric expansion. The superior electrochemical properties of this new material were further established by the retention of 99.4% of the energy capacity even after 775 charge and discharge cycles. In addition to the exceptional energy storage capabilities, the material also exhibited great mechanical stability throughout the testing process.

The results strongly indicate the superiority of new SiMP-based active anode materials. Indeed, these materials have opened up new avenues for the application of silicon in next-generation secondary lithium-ion batteries. The scalability of this synthetic process can help bridge the gap between laboratory research and industrial applications in the field of energy storage. This is particularly important for producing low-cost electric vehicles, which can significantly reduce carbon emissions. Professor Matsumi highlights this important application of their study by stating, “Our methodology provides an efficient pathway for the development of high-performance anode materials for energy-efficient lithium-ion batteries, which is a critical component in creating a sustainable and energy-efficient environment. low consumption. carbon tomorrow.

Sarah C. Figueiredo