Lithium batteries have revolutionized mobile electronic devices and are used in new energy devices, but further improvements in life and power will require new technologies. One option is lithium metal batteries, which have longer battery life and faster charging speeds, but there are problems with this technology. Lithium deposits, called dendrites, tend to grow on the anode and can form a short circuit, causing battery failure, fire or explosion.

At present, researchers from the Institute of Chemistry, Chinese Academy of Sciences, University of Chinese Academy of Sciences, and China High Pressure Science and Technology Research Center have designed a membrane separator based on carbon allotropes. It is called graphene, which acts as a lithium ion filter to prevent dendritic growth [Shangetal. Material.10(2018) 191-199].

Lithium metal batteries are similar in concept to lithium batteries, but rely on lithium metal anodes. During the discharge process, the lithium anode provides electrons to the cathode through an external circuit. However, when charging, lithium is deposited on the anode. In this process, unwanted dendrites will form.

This is the function of the diaphragm. The membrane separator made of ultra-thin (10nm) graphite diacetylene (two-dimensional hexagonal carbon atom monolayer connected by succinic acid chains) has important practical value. Graphite diacetylene not only has elasticity and toughness, but its chemical structure also forms a uniform pore network, allowing only one lithium ion to pass through. This regulates the movement of ions through the membrane, resulting in a highly uniform diffusion of ions. Importantly, this characteristic effectively inhibits the growth of lithium dendrites.

Li Yuliang of the Institute of Chemistry of the Chinese Academy of Sciences, who led the research, explained that lithium dendrites can stabilize the solid electrolyte interface, thereby extending the life of the device and the Coulomb power. Prevent tree-shaped short circuit and reach the battery safely.

Researchers believe that graphene-diethyne films can overcome some of the thorny problems faced by lithium batteries and other alkaline metal batteries.

Li said that graphitic diacetylene is a getter material with hyper-conjugated structure, inherent band gap, natural macroporous structure and semiconductor function. It provides a huge prospect for solving major scientific problems in this field.

Two-dimensional data is also very simple, and it is easy to obtain under general laboratory conditions.

Researchers told reporters that although more work needs to be done to improve the quality of graphite-diacetylene films on a large scale, we believe that graphite-diacetylene may have a serious impact on the safety of lithium batteries.