Recently, researcher Tang Yongbing (Corresponding Author, Unit 1) and research team of Hunan University, Professor Ma Jianmin (Corresponding Author) and Jilin Normal University Professor Yang Jinghai (Corresponding Author) (Author) The self-template method was used to successfully prepare a three-dimensional porous microcrystalline carbon material for the positive electrode of a dual-ion battery with large capacity and long cycle life. Related research results are titled High-Performance Cathode based on Self-Templated 3D Porous Microcrystalline Carbon with Improved Anion Adsorption and Intercalation. Published online in the international materials journal Advanced Functional Materials (DOI: 10.1002 / adfm.201806722).
Due to their low cost and environmental friendliness, dual-ion batteries have received much attention recently. The cathode of a dual-ion battery usually uses graphite, and relies on anion intercalation / de-intercalation to achieve charge and discharge. Due to the large anion size, the capacity of anion-intercalated graphite is limited. At the same time, conventional graphite will undergo volume expansion after inserting anions, causing graphite to peel off, and eventually causing rapid capacity decay. In addition, for traditional graphite materials, the anion insertion process is limited to the edges of the graphite particles, resulting in insufficient charge-discharge rate performance of the battery.
Based on the above considerations, Tang Yongbing and his research team members Zhang Ge (first author), Ou Xuewu (joint work), Cui Chunyu (joint work) and others designed and prepared a three-dimensional porous microcrystalline carbon by self-template method. This carbon material with a microcrystalline structure and a certain surface area not only facilitates the intercalation of anions, but also facilitates the adsorption of anions, which can significantly increase the capacity of the positive electrode. In addition, the porous structure increases the anion intercalation and adsorption sites, which effectively improves the charge and discharge rate of the dual-ion battery; and the three-dimensional structure design can alleviate the volume expansion caused by the anion intercalation to a certain extent and improve the structural stability of the material Sex. The sodium-based dual-ion battery using this carbon material as a positive electrode has a discharge capacity of 168.0 mAh g-1 at a current density of 0.3 A g-1, which is one of the best performances reported so far. At the same time, after cycling 2000 times at a current density of 1 A g-1, the capacity retention rate was 70%. This research provides new ideas for the development of high-performance dual-ion battery anode materials.