The capacity of MoS2 composite anode is twice that of graphite
As we all know, from mobile phones to drones and electric cars, lithium-ion batteries are everywhere. Lithium-ion batteries stand out from many chemical batteries due to their environmental protection, small size, light weight, and no memory effect, but this does not mean that the battery does not have any shortcomings. Lithium-ion batteries have not been widely used in aviation, navigation and national defense due to their low energy density and high safety risks.
As a representative material for the negative electrode of commercial lithium-ion batteries, although graphite has good stability and conductivity, it cannot store too much lithium ions between layers, thus significantly reducing the capacity of the battery. Normally, the more active lithium ions stored in the electrode, the greater the capacity of the battery, and the faster the diffusion of these lithium ions, the higher the efficiency of the battery.
In order to alleviate the problem of poor lithium storage performance of graphite anodes, the researchers said that MoS2 can be used to replace graphite anodes.
MoS2 is a two-dimensional layered material with a natural adjustable band gap. Its unique properties have attracted great attention from scientific researchers and have important application prospects in the fields of microelectronics, optoelectronics, and batteries.
In 1980, rechargeable lithium batteries began to use MoS2 anodes, which can provide more power than the standard rechargeable batteries at the time-nickel-cadmium batteries, and have no memory effect. These advantages are mainly due to the layer spacing of MoS2 is almost twice that of the graphite layer, which can accommodate more lithium ions. However, this lithium battery is extremely prone to fire and explosion due to the use of highly active lithium metal. In addition, the cycle performance of the MoS2 battery is poor, and the capacity is severely attenuated after a few operations. As a result, the commercial interest in molybdenum disulfide has greatly diminished.
However, recent studies have shown that molybdenum disulfide and graphene composite anode materials can effectively make up for the shortcomings of graphite's low storage capacity and poor cycle performance of MoS2. The advantages of MoS2/graphene composite anode materials are: (1) MoS2 has a strong lithium ion storage capacity and a faster ion diffusion rate; (2) It has the extraordinary conductivity of graphene, which can avoid serious degradation of early MoS2 battery performance The problem.
In short, if the lithium ion battery produced in the future can use MoS2/graphene composite material as the anode, the capacity and cycle life will be greatly improved. It is reported that molybdenum disulfide can also be well used in lithium-air batteries and sodium-ion batteries.