Understanding the Charge Storage Mechanism of Nickel–Cobalt Sulfides/Selenides/Phosphides in an Alkaline Electrolyte: Pseudocapacitive or Battery-Type?

作者：Kai Shu, Hong‐Ming Hu, Zhenyao Peng, Jiale Zhao, Zhouji Zhong, Xiao Tang, Yi Lu, Xianju Zhou, Yanhong Li · 发表于：ACS Applied Energy Materials · 年份：2025 · DOI：10.1021/acsaem.5c00414 · 被引用次数：3 · 研究领域：Advancements in Battery Materials、Supercapacitor Materials and Fabrication、Advanced battery technologies research

Over the past decades, nanomaterials have enabled battery materials to achieve rapid redox kinetics comparable to pseudocapacitive materials due to the shortened ion diffusion length and high surface/interface exposure. Consequently, the boundaries between pseudocapacitive and battery materials have become quite blurred, and the distinction between the two concepts has become unclear. Typically, nickel/cobalt/nickel–cobalt sulfides/selenides/phosphides are widely reported as active materials for supercapacitor applications in an alkaline electrolyte. They are described as pseudocapacitive materials despite exhibiting electrochemical features similar to those of battery materials. Therefore, in this work, the electrochemical behaviors of nickel–cobalt sulfides/selenides/phosphides are systematically and comprehensively analyzed. We demonstrate why it is inappropriate to describe them as pseudocapacitive electrode materials in an alkaline electrolyte. This paper does not discredit the extensive experimental work conducted within the realm of pseudocapacitance but aids in comprehending the distinctions between pseudocapacitive and battery materials more thoroughly, thereby avoiding the definition confusion. More importantly, this clear differentiation will enable the rational selection of material classes and corresponding structural engineering approaches tailored to specific application requirements.