Fundamental mechanisms of energy storage, corrosion, sensing, and multiple biological functionalities are directly coupled to electrical processes and ionic dynamics at solid-liquid interfaces. In many cases, these processes are spatially inhomogeneous taking place at grain boundaries, step edges, point defects, ion channels, etc and possess complex time and voltage dependent dynamics. This necessitates time-resolved and real-space probing of these phenomena. In this review, we discuss the applications of force-sensitive voltage modulated scanning probe microscopy (SPM) for probing electrical phenomena at solid-liquid interfaces. We first describe the working principles behind electrostatic and Kelvin probe force microscopies (EFM & KPFM) at the gas-solid interface, review the state of the art in advanced KPFM methods and developments to (i) overcome limitations of classical KPFM, (ii) expand the information accessible from KPFM, and (iii) extend KPFM operation to liquid environments. We briefly discuss the theoretical framework of electrical double layer (EDL) forces and dynamics, the implications and breakdown of classical EDL models for highly charged interfaces or under high ion concentrations, and describe recent modifications of the classical EDL theory relevant for understanding nanoscale electrical measurements at the solid-liquid interface. We further review the latest achievements in mapping surface charge, dielectric constants, and electrodynamic and electrochemical processes in liquids. Finally, we outline the key challenges and opportunities that exist in the field of nanoscale electrical measurements in liquid as well as providing a roadmap for the future development of liquid KPFM.

中文翻译：

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通过先进的 KPFM 技术在液体中进行纳米级电测量：综述

能量存储、腐蚀、传感和多种生物功能的基本机制与固液界面的电过程和离子动力学直接相关。在许多情况下，这些过程在晶界、台阶边缘、点缺陷、离子通道等处发生空间不均匀，并且具有复杂的时间和电压相关动力学。这需要对这些现象进行时间分辨和实空间探测。在这篇综述中，我们讨论了力敏电压调制扫描探针显微镜 (SPM) 在探测固液界面电现象中的应用。我们首先描述了气固界面静电和开尔文探针力显微镜（EFM & KPFM）背后的工作原理，回顾先进 KPFM 方法和发展的最新技术，以 (i) 克服经典 KPFM 的局限性，(ii) 扩展可从 KPFM 获取的信息，以及 (iii) 将 KPFM 操作扩展到液体环境。我们简要讨论了双电层 (EDL) 力和动力学的理论框架、经典 EDL 模型对高电荷界面或高离子浓度下的影响和分解，并描述了与理解纳米级电测量相关的经典 EDL 理论的最新修改在固液界面。我们进一步回顾了在绘制表面电荷、介电常数以及液体中的电动和电化学过程方面的最新成果。最后，