Peking University, Jan. 18, 2017: Battery science and technology are of current interest. While the specific capacity of the commercially used graphite anode for lithium battery is limited to 372 mAh/g. Extensive efforts have been devoted to improve the performance but not much progress was made during the past 25 years. Inspired by the 2016 Nobel Prize in Physics for topological state and phases of materials, Professor Sun Qiang and his students (Liu Junyi and Wang Shuo in the Department of Materials Science and Engineering) explored the possibility of using all-carbon-based porous topological semimetal (ACTS) for Li-ion battery anode material motivated by the following two facts: (1) ACTS has the merits of intrinsic high electronic conductivity and ordered porosity for the storage and transport of Li ions; (2)  carbon is abundant in resources, flexible in bonding, and ever changing in morphology.{Zhang, 2015 #435;Zhang, 2013 #436}

Taking topological semimetal bco-C₁₆ as an example, the researchers show that the bco-C₁₆ anode is able to have an increased specific capacity of 558 mAh/g (Li-C₄) compared with the graphite (Li-C₆). Moreover, Li ions in bco-C₁₆ exhibit a remarkable one dimensional (1D) migration features, the energy barrier decreases with increasing Li insertion and can reach 0.019 eV at high Li ions concentration, the average voltage is as low as 0.23 V, and the volume change during the operation is comparable to that of graphite, indicating that ACTS structures can be promising anode materials with high specific capacity, fast ion kinetics and slight volume change during operation. More details can be found at: http://www.pnas.org/content/early/2017/01/04/1618051114

This study bridges the gap between the lithium battery and topological state of matter, which would not only pave a novel pathway for design of high performance anode materials going beyond graphite but also enrich the applications of topological materials.

All-carbon-based porous topological semimetal Li-ion battery

Edited by: Zhang Jiang
Source: College of Engineering