Understanding the performance of graphene devices in contact with highly concentrated aqueous electrolytes is key to integrating graphene into next-generation devices operating in sea water environments, biosensors, and high-density energy production/storage units. Despite significant efforts toward interpreting the structure of the electrochemical double layer at high concentrations, the interface between graphene-based materials and concentrated aqueous solutions has remained vaguely described. In this study, we demonstrate the use of graphene-based chemiresistors as a technique to indirectly quantify the experimental screening length of concentrated electrolytes that could clarify the interpretation of electrochemical measurements conducted at low ionic strength. We report a breakdown of the Debye–Hückel theory in the proximity of graphene surfaces at lower concentrations (10–50 mM) than previously reported for other systems, depending on cation size, dissolved oxygen concentration, and degree of graphene defectivity.

了解石墨烯器件与高浓度水性电解质接触时的性能是将石墨烯集成到在海水环境中运行的下一代器件、生物传感器和高密度能源生产/存储单元的关键。尽管在解释高浓度电化学双层结构方面做出了巨大努力，但石墨烯基材料和浓水溶液之间的界面仍然模糊描述。在这项研究中，我们展示了使用基于石墨烯的化学电阻器作为一种技术来间接量化浓缩电解质的实验筛选长度，这可以澄清在低离子强度下进行的电化学测量的解释。