The development of pseudocapacitive materials for energy‐oriented applications has stimulated considerable interest in recent years due to their high energy‐storing capacity with high power outputs. Nevertheless, the utilization of nanosized active materials in batteries leads to fast redox kinetics due to the improved surface area and short diffusion pathways, which shifts their electrochemical signatures from battery‐like to the pseudocapacitive‐like behavior. As a result, it becomes challenging to distinguish “pseudocapacitive” and “battery” materials. Such misconceptions have further impacted on the final device configurations. This Review is an earnest effort to clarify the confusion between the battery and pseudocapacitive materials by providing their true meanings and correct performance metrics. A method to distinguish battery‐type and pseudocapacitive materials using the electrochemical signatures and quantitative kinetics analysis is outlined. Taking solid‐state supercapacitors (SSCs, only polymer gel electrolytes) as an example, the distinction between asymmetric and hybrid supercapacitors is discussed. The state‐of‐the‐art progress in the engineering of active materials is summarized, which will guide for the development of real‐pseudocapacitive energy storage systems.

中文翻译：

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伪电容器及其性能指标的真实含义：不对称与混合超级电容器。

近年来，由于其具有高能量存储能力和高功率输出的特性，面向能源应用的伪电容材料的开发引起了人们的极大兴趣。然而，由于表面积的增加和扩散路径的缩短，纳米级活性材料在电池中的使用导致了快速的氧化还原动力学，这将其电化学特征从类电池的行为转变为类电容的行为。结果，区分“伪电容”和“电池”材料变得具有挑战性。这样的误解进一步影响了最终的设备配置。本评论是通过提供电池的真实含义和正确的性能指标来澄清电池和假电容材料之间的混淆的认真工作。概述了一种使用电化学特征和定量动力学分析来区分电池类型和假电容材料的方法。以固态超级电容器（SSC，仅聚合物凝胶电解质）为例，讨论了不对称超级电容器与混合超级电容器之间的区别。总结了活性材料工程技术的最新进展，这将为实际伪电容储能系统的开发提供指导。