The researchers found that alumina coating can protect the positive electrode of the battery and pro

      According to foreign media reports, anulekha haridas, a postdoctoral researcher at Rice University, used the constructed lithium-ion full cell to test the effect of alumina coating on the positive electrode. The nano coating can protect the anode from degradation.

Researchers at Rice University's Brown School of engineering applied a thin layer of aluminum oxide on the common positive electrode, and found that this would make the battery performance of electric vehicles better and have more powerful off grid energy storage capacity.

The American Chemical Society describes a previously unknown mechanism in its study. Under this mechanism, lithium is trapped in the battery, which limits the number of charges and discharges at full power, but it does not make people lose hope. Sibani Lisa biswal, an engineer at Les chemical and biomolecular laboratory, found a point in the battery to provide a smooth cycle for related applications by keeping the storage capacity of the battery from being maximized.

Biswal said that the traditional lithium-ion battery uses a graphite based negative electrode with a capacity of less than 400mah / g. In contrast, the potential capacity of the silicon anode may be 10 times that of it. However, there are also defects in the negative electrode: when silicon and lithium combine to form an alloy, silicon will expand, causing pressure on the negative electrode. The team used porous silicon to build the battery and limited its capacity to 1000mah / g. the results showed that the tested battery cycle was stable and maintained good capacity. "Capacitations put a lot of pressure on materials," biswal said. This strategy can obtain capacity without generating the same pressure. 1000 MAH / G is a big leap. "

The team, led by anulekha haridas, a postdoctoral researcher, tested the concept of a high-capacity porous silicon anode (replacing graphite) with a high-pressure nickel manganese cobalt oxide (NMC) anode. After hundreds of cycles, lithium-ion batteries show stable recyclability and 1000 MAH / g capacity. Through atomic layer deposition, some positive electrodes are coated with 3nm alumina layer, while others are not. The researchers found that in the presence of hydrofluoric acid, alumina coating can prevent the decomposition of the positive electrode. Hydrofluoric acid is formed by the invasion of water (even trace water) into the liquid electrolyte. The test results show that alumina can accelerate the charging speed and reduce the times of charging and discharging.

According to haridas, lithium is rapidly transported in alumina and may be trapped in large quantities. Researchers have found that silicon anode can capture lithium in large quantities, making it unsuitable for power equipment. But this is the first report that alumina itself can absorb lithium until it is saturated. From this point of view, the layer can be used as a catalyst to promote the ion migration of the positive electrode. "This lithium capture mechanism effectively protects the positive electrode and maintains a stable capacity and energy density for the entire battery," haridas said