Pan Hongwei, Xu Zhengshuai, Wei Zhaoyang, Liu Xin, Xu Minghan, Zong Chengzhong, Li Weijie, Cui Guanglei, Cao Lan, Wang Qingfu
Qingdao University of Science and Technology, Qingdao 266045, China.
Institute for Superconducting and Electronic Materials, University of Wollongong. Wollongong, New South Wales 2522 Australia.
ACS Appl Mater Interfaces. 2022 Jul 14. doi: 10.1021/acsami.2c08038.
Silicon (Si), a high-capacity lithium-ion battery anode material, has aroused wide attention. Its further practical application has been limited by its huge volume change during the cycle. To reduce this defect, the double cross-linked product of glycinamide hydrochloride modified poly(acrylic acid) (PAG) and epoxidized natural rubber (ENR) was developed as a water-based binder to obtain sufficient elasticity and a sufficiently strong adhesive force. Due to the double cross-linked structures in the system, the binder was enabled to effectively disperse and transfer the stress generated by the volume expansion of the Si particles and keep the integrity of the electrode during the cycle, thus obtaining excellent cycle performance. When the current density was 1 A g, PE55 (PAG: ENR = 1:1 cross-linked polymer) electrode still achieved a specific capacity of 2322.2 mAh g after 100 cycles of constant current charge and discharge, and PE55 binder exhibited excellent bonding properties (4.45 N) and mechanical properties (stress: 5.51 MPa, strain: 87.4%). The comparison of poly(acrylic acid) (PAA) electrodes suggests that the introduction of elastic polymer and the construction of double cross-linked structures can increase the stability of Si anodes.
硅（Si）作为一种高容量锂离子电池负极材料，已引起广泛关注。其进一步的实际应用受到循环过程中巨大体积变化的限制。为了减少这一缺陷，开发了甘氨酰胺盐酸盐改性聚丙烯酸（PAG）与环氧化天然橡胶（ENR）的双交联产物作为水性粘结剂，以获得足够的弹性和足够强的粘合力。由于体系中的双交联结构，该粘结剂能够有效分散和转移硅颗粒体积膨胀产生的应力，并在循环过程中保持电极的完整性，从而获得优异的循环性能。当电流密度为1 A g时，PE55（PAG：ENR = 1：1交联聚合物）电极在恒流充放电100次循环后仍具有2322.2 mAh g的比容量，并且PE55粘结剂表现出优异的粘结性能（4.45 N）和机械性能（应力：5.51 MPa，应变：87.4%）。聚丙烯酸（PAA）电极的对比表明，弹性聚合物的引入和双交联结构的构建可以提高硅负极的稳定性。
