Zhang Jingmin, Fan Sijia, Wang Hui, Qian Jiangfeng, Yang Hanxi, Ai Xinping, Liu Jincheng
Hubei Key Lab of Electrochemical Power Sources, College of Chemistry & Molecule, Science , Wuhan University , Wuhan 430072 , China.
Research Institute , EVE Battery Corporation Limited , Huizhou 516006 , China.
ACS Appl Mater Interfaces. 2019 Apr 10;11(14):13251-13256. doi: 10.1021/acsami.9b00939. Epub 2019 Mar 26.
Silicon is now well-recognized to be a promising alternative anode for advanced lithium-ion batteries because of its highest capacity available today; however, its insufficiently high Coulombic efficiency upon cycling remains a major challenge for practical application. To overcome this challenge, we have developed a facile mechanochemical method to synthesize a core-shell-structured Si/polyphenylene composite (Si/PPP) with a n-type conductive PPP layer tightly bonded in a planar orientation to the surfaces of Si nanocores. Because of its compactness and flexibility, the outer PPP layer can protect the Si core from contacting the electrolyte and maintaining the structural stability of electrode/electrolyte interface during cycles. As a result, the Si/PPP anode demonstrated a high reversible capacity of ∼2387 mAh g, a stable cycleability with 88.5% capacity retention over 500 cycles, and, particularly, a high Coulombic efficiency of 99.7% upon extended cycling, offering a new insight for future development of high-capacity and cycle-stable Si anode.
由于硅具有当今可用的最高容量，现在它已被公认为是先进锂离子电池有前景的替代负极材料；然而，其在循环过程中库仑效率不够高仍然是实际应用中的一个主要挑战。为了克服这一挑战，我们开发了一种简便的机械化学方法来合成核壳结构的硅/聚亚苯基复合材料（Si/PPP），其中n型导电的聚亚苯基层以平面取向紧密结合在硅纳米核的表面。由于其紧密性和柔韧性，外部的聚亚苯基层可以保护硅核不与电解质接触，并在循环过程中保持电极/电解质界面的结构稳定性。结果，Si/PPP负极表现出约2387 mAh g的高可逆容量、在500次循环中容量保持率为88.5%的稳定循环性能，特别是在长时间循环后具有99.7%的高库仑效率，为高容量和循环稳定的硅负极的未来发展提供了新的思路。
