Materials Science and Engineering Program & Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712-1591, USA.
Small Methods. 2023 Jul;7(7):e2201680. doi: 10.1002/smtd.202201680. Epub 2023 Apr 25.
All-solid-state batteries (ASSBs) employing Li-metal anodes and inorganic solid electrolytes are attracting great attention due to high safety and energy density for next-generation energy storage devices. However, the volume change of cathode active materials can cause contact loss, resulting in charge carrier isolation, heterogeneous current distribution, and poor electrochemical properties in ASSBs. Here, a simple, yet effective, solvent-free electrode engineering approach with polytetrafluoroethylene (PTFE) as a binder for ASSBs is reported, enabling intimate contact and stable interfaces with the cathode. It is substantiated that the crystallinity of PTFE can be controlled depending on the heat history, and highly crystalline PTFE displays robust mechanical properties. High-nickel LiNi Mn Co O cathode prepared with crystalline PTFE show improved cycle and rate performances in ASSBs. In addition, it is revealed that the intimate contact between cathode particles with a stable cathode electrolyte layer is maintained during cycling by postmortem studies. This simple engineering method can be applied to prepare cathodes with a variety of active materials and solid electrolytes in ASSBs.
全固态电池（ASSBs）采用锂金属阳极和无机固体电解质，由于其在下一代储能设备中具有高安全性和能量密度，因此备受关注。然而，正极活性材料的体积变化会导致接触损失，从而导致电荷载流子隔离、不均匀电流分布以及 ASSBs 中较差的电化学性能。在这里，报道了一种简单而有效的无溶剂电极工程方法，该方法使用聚四氟乙烯（PTFE）作为 ASSBs 的粘合剂，可实现与正极的紧密接触和稳定界面。已经证实，PTFE 的结晶度可以根据热历史进行控制，并且高结晶度的 PTFE 具有很强的机械性能。用结晶 PTFE 制备的高镍 LiNi0.5Mn0.3Co0.2O2 正极在 ASSBs 中表现出改善的循环和倍率性能。此外，通过事后研究揭示了在循环过程中通过稳定的正极电解质层保持正极颗粒之间的紧密接触。这种简单的工程方法可以应用于制备具有各种活性材料和固体电解质的 ASSBs 正极。
