Kim Jaewon, Kim Min-Seob, Lee Youngseok, Kim Shin-Yeong, Sung Yung-Eun, Ko Seung Hwan
Applied Nano and Thermal Science Lab, Department of Mechanical Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Apr 20;14(15):17340-17347. doi: 10.1021/acsami.2c00844. Epub 2022 Apr 6.
Silicon (Si) anodes in lithium-ion batteries (LIBs) suffer from huge volume changes that lead to a rapid capacity decrease and short cycle life. A conductive binder can be a key factor to overcome this issue, maintaining continuous electron paths under pulverization of Si. Herein, composites of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly(vinyl alcohol) (PVA) are augmented with poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) as a binder for Si anodes, which forms hierarchical structures due to different chain lengths of PEG and PEO. The integration of PEG and PEO imparts higher electrical conductivity (∼40%) and stretchability (∼60%) through densely spread hydrogen bonding and cross-linking, compared to conductive polymer binders with PEO or PEG. Further, a silver nanowire (AgNW) network combined with the polymer binder supplies an effective three-dimensional (3D) electrical path, sufficient void space to buffer the volume changes, and highly adhesive interaction with the current collector. The fabricated Si anode demonstrates a higher specific capacity of 1066 mAh g at 0.8 A g after 100 cycles and improved rate capability.
锂离子电池（LIBs）中的硅（Si）阳极会经历巨大的体积变化，这会导致容量迅速下降和循环寿命缩短。导电粘结剂可能是克服这一问题的关键因素，它能在硅粉化过程中维持连续的电子路径。在此，聚（3,4-乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT:PSS）与聚（乙烯醇）（PVA）的复合材料，通过添加聚（乙二醇）（PEG）和聚（环氧乙烷）（PEO）作为硅阳极的粘结剂，由于PEG和PEO链长不同而形成了分层结构。与含PEO或PEG的导电聚合物粘结剂相比，PEG和PEO的整合通过密集分布的氢键和交联赋予了更高的电导率（约40%）和拉伸性（约60%）。此外，与聚合物粘结剂结合的银纳米线（AgNW）网络提供了有效的三维（3D）电子路径、足够的空隙空间来缓冲体积变化以及与集流体的高粘附相互作用。制备的硅阳极在100次循环后，在0.8 A g电流密度下具有1066 mAh g的更高比容量，并提高了倍率性能。
