Lithium-ion batteries are an essential part of modern technology, providing reliable power for smartphones, laptops, electric cars and other devices. However, the capacity and performance of lithium-ion batteries still have a lot of room for improvement, especially in the selection of anode materials.

Q1 anode material

The anode of lithium-ion batteries is mainly made of graphite or carbon fiber, which can store a certain amount of lithium ions, but it is not the most ideal material. Silicon is a more promising anode material, which can store ten times more lithium ions than graphite, greatly increasing the capacity and energy density of batteries. If the anode were made entirely of silicon, the capacity of the battery could theoretically be increased by 70%.

Q2 How can we reduce the negative impact of silicon?

Silicon also has a fatal drawback, which is that it can undergo huge volume changes during charging and discharging. When lithium ions enter silicon, the silicon will expand by 300%, and when lithium ions leave silicon, the silicon will shrink back to its original size. This repeated expansion and contraction causes the silicon material to break and flake, reducing the performance and life of the battery. Therefore, current research is looking for a way to reduce or eliminate the negative effects of changes in the volume of silicon while maintaining its high capacity.

Recently, a research team from Drexel University in the United States and Trinity College Dublin in Ireland made a breakthrough by using a special material called MXene and mixing it with silicon nanoparticles to make a new type of silicon-MXene anode. MXene is a two-dimensional inorganic compound first discovered by Drexel University in 2011, which has excellent electrical conductivity, mechanical strength and chemical stability. More than 30 different types of MXene materials have been discovered, and they can be tuned and optimized for different application needs.

The research team took two MXene materials, titanium carbide (Ti3C2Tx) and titanium carbonitride (Ti3CNx), and mixed them with graphene into a solution. They then mixed the solution with silicon nanoparticles and made the thin-film anode material through a slurry casting process. This method is simple and effective, allowing for mass production of anodes of different shapes and sizes.
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