Long Jiang, He Wenjie, Liao Haojie, Ye Wenjun, Dou Hui, Zhang Xiaogang
Jiangsu Key Laboratory of Electrochemical Energy Storage Technology, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P. R. China.
ACS Appl Mater Interfaces. 2023 Mar 1;15(8):10726-10734. doi: 10.1021/acsami.2c21689. Epub 2023 Feb 14.
Polymer binders play an important role in enhancing the electrochemical performance of silicon-based anodes to alleviate the volume expansion for lithium-ion batteries. It is difficult for common one-dimensional (1D) linear binders to limit the volume expansion of a silicon-based electrode when combined with silicon-based particles with scant binding points. Therefore, it is necessary to design a three-dimensional (3D) network structure, which has multiple binding points with the silicon particles to dissipate the mechanical stress in the continuous charge and discharge circulation. Here, a covalent and hydrogen bond synergist 3D network green binder (poly(acrylic acid) (PAA)-dextrin 9 (Dex)) was prepared by the simple thermal condensation of a one-dimensional liner binder PAA and Dex in the electrode fabrication process. The optimized SiO@PAA-Dex electrode exhibits an initial Coulombic efficiency (ICE) of 82.4% at a current density of 0.2 A g. At a high current density of 1 A g, it retains a capacity of 607 mAh g after 300 cycles, which is approximately twice as high as that of the SiO@PAA electrode. Furthermore, the results of electrochemical dilatometry (ECD) and characterization of electrode structures demonstrate that the PAA-Dex binder can effectively buffer the huge volume change and maintain the integrity of the SiO electrodes. The research overcomes the low electrochemical stability difficulty of the 3D binder and sheds light on developing the simple fabrication procedure of an electrode.
聚合物粘结剂在提高硅基负极的电化学性能以缓解锂离子电池的体积膨胀方面发挥着重要作用。当与具有很少结合点的硅基颗粒结合时，普通的一维（1D）线性粘结剂很难限制硅基电极的体积膨胀。因此，有必要设计一种三维（3D）网络结构，它与硅颗粒有多个结合点，以在连续的充放电循环中消散机械应力。在此，通过在电极制造过程中一维线性粘结剂聚丙烯酸（PAA）和糊精9（Dex）的简单热缩合制备了一种共价和氢键协同的3D网络绿色粘结剂（聚（丙烯酸）（PAA）-糊精9（Dex））。优化后的SiO@PAA-Dex电极在电流密度为0.2 A g时的初始库仑效率（ICE）为82.4%。在1 A g的高电流密度下，经过300次循环后，它保持607 mAh g的容量，约为SiO@PAA电极的两倍。此外，电化学膨胀法（ECD）和电极结构表征结果表明，PAA-Dex粘结剂可以有效缓冲巨大的体积变化并保持SiO电极的完整性。该研究克服了3D粘结剂电化学稳定性低的难题，并为开发简单的电极制造工艺提供了思路。
