Construction of Rich Conductive Pathways from Bottom to Top: A Highly Efficient Charge‐Transfer System Used in Durable Li/Na‐Ion Batteries at −20 °C

• Published in: Chemistry : a European journal 2020-10, Vol.26 (58), p.13274-13281
• Main Authors: Xue, Yan, Li, Huanhuan, Zhang, Yuting, Zhuo, Kelei, Bai, Guangyue
• Format: Article
• Language: English
• Subjects: Batteries; Charge transfer; Chemical reactions; Chemistry; Coated electrodes; Construction; Electrochemical analysis; Electrochemistry; Electrode materials; Electrodes; flake graphites; Foils; Lithium; lithium/sodium storage; low-temperature performance; nanofoam structures; Nanoparticles; Nitrogen; Rechargeable batteries; Sodium; Sodium-ion batteries; Specific capacity; Storage batteries; Structural stability; Sulfurization
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202002317

The construction of potential electrode materials with wide temperature property for high‐energy‐density secondary batteries has attracted great interest in recent years. Herein, a hybrid electrode, consisting of a nitrogen‐doped carbon/α‐MnS/flake graphite composite (α‐MnS@N‐C/FG), is prepared through a post‐sulfurization route. In the α‐MnS@N‐C/FG composite, α‐MnS nanoparticles wrapped by the N−C layer are uniformly embedded onto FG, forming a novel nanofoam structure. The as‐obtained α‐MnS@N‐C/FG shows excellent lithium/sodium storage performance, with a specific capacity of 712 mA h g−1 in the 700th cycle at 1.0 A g−1 or 186.4 mA h g−1 in the 100th cycle at 100 mA g−1 using lithium or sodium foil as the counter electrode, respectively. Moreover, even operated at −20 °C, the α‐MnS@N‐C/FG can still attain a high specific capacity of 350 mA h g−1 after 50 cycles at 100mA g−1 for LIBs. This exceptional electrochemical response is attributed to the synergetic effect of the smart design of a hybrid nanofoam structure, in which the FG skeleton and N‐C coating layer can significantly enhance the conductivity of the whole electrode from bottom to top. Accordingly, the enhanced redox kinetics endow the electrode with pseudocapacitive‐dominated electrochemical behavior, leading to fast electrode reactions and robust structural stability in the whole electrode. Electrode design: The rational design of α‐MnS nanoparticles wrapped by a N‐doped carbon layer and uniformly embedded onto flake graphite (α‐MnS@N‐C/FG) is proposed. In the obtained composite, the FG skeleton and N‐C coating layer can significantly improve the conductivity of the whole electrode from bottom to top, thus enhancing the redox kinetics and leading to superb Li/Na‐storage performances of the electrode over a wide temperature range.