Lithium-ion batteries (LIB) as energy supply and storage systems have been widely used in electronics, electric vehicles, and utility grids. However, there is an increasing demand to enhance the energy density of LIB. Therefore, the development of new electrode materials with high energy density becomes significant. Although many novel materials have been discovered, issues remain as (1) the weak interaction and interface problem between the binder and the active material (metal oxide, Si, Li, S, etc.), (2) large volume change, (3) low ion/electron conductivity, and (4) self-aggregation of active materials during charge and discharge processes. Currently, the binder-free electrode serves as a promising candidate to address the issues above. Firstly, the interface problem of the binder and active materials can be solved by fixing the active material directly to the conductive substrate. Secondly, the large volume expansion of active materials can be accommodated by the porosity of the binder-free electrode. Thirdly, the ion and electron conductivity can be enhanced by the close contact between the conductive substrate and the active material. Therefore, the binder-free electrode generally exhibits excellent electrochemical performances. The traditional manufacture process contains electrochemically inactive binders and conductive materials, which reduces the specific capacity and energy density of the active materials. When the binder and the conductive material are eliminated, the energy density of the battery can be largely improved. This review presents the preparation, application, and outlook of binder-free electrodes. First, different conductive substrates are introduced, which serve as carriers for the active materials. It is followed by the binder-free electrode fabrication method from the perspectives of chemistry, physics, and electricity. Subsequently, the application of the binder-free electrode in the field of the flexible battery is presented. Finally, the outlook in terms of these processing methods and the applications are provided.

中文翻译：

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无粘合剂电极及其在锂离子电池中的应用。

锂离子电池（LIB）作为能源供应和存储系统已广泛用于电子，电动汽车和公用电网中。然而，对提高LIB的能量密度的需求不断增加。因此，具有高能量密度的新型电极材料的开发变得重要。尽管已经发现了许多新型材料，但仍然存在以下问题：（1）粘合剂与活性材料（金属氧化物，Si，Li，S等）之间的弱相互作用和界面问题；（2）体积变化大；（3） ）较低的离子/电子电导率，以及（4）在充电和放电过程中活性物质的自聚集。当前，无粘合剂电极可作为解决上述问题的有前途的候选者。首先，粘合剂和活性材料的界面问题可以通过将活性材料直接固定到导电基材上来解决。其次，无粘合剂电极的孔隙率可以容纳活性材料的大体积膨胀。第三，可以通过导电基板和活性材料之间的紧密接触来增强离子和电子的导电性。因此，无粘合剂电极通常表现出优异的电化学性能。传统的制造过程包含电化学惰性的粘合剂和导电材料，这降低了活性材料的比容量和能量密度。当消除粘合剂和导电材料时，可以大大提高电池的能量密度。这篇评论介绍了准备工作，应用，无粘合剂电极的外观。首先，引入不同的导电基底，其用作活性材料的载体。其次是从化学，物理和电学角度出发的无粘合剂电极的制造方法。随后，提出了无粘合剂电极在柔性电池领域中的应用。最后，提供了关于这些处理方法和应用的展望。