Dataset of "Wide electrochemical stability window of boron-doped microcrystalline diamond electrode in NaNO3 water-in-salt electrolytes"

Expanding the electrochemical stability window (ESW) of aqueous electrolytes can contribute to the high energy density of electrochemical energy storage devices and supercapacitors (SC). Here we demonstrate unique electrochemical interaction in two and three-electrode configurations of sodium nitrate (NaNO3) water-in-salt (WiS) electrolyte in a wide range of concentrations (1-12 m) with an electrode made of boron-doped microcrystalline diamond (B-MCDE, grain size ~ 1 m) deposited by a microwave plasma Chemical Vapor Deposition (CVD) process. Compared to a commercial glassy carbon electrode (C-GCE), the extension of ESW up to ~ 3 V was obtained. In the frequency range of 10 mHz - 100 kHz, the B-MCDE also demonstrated better conductive (down to Rct of 50 Ω) and capacitive (up to Cdl 3.2 µF) properties compared to C-GCE for all investigated electrolyte concentrations, where the appropriate equivalent circuit was identified. The best performance was obtained for 8 m WiS concentration at neutral pH and room temperature, whereas 12 m WiS was unstable, as confirmed by Raman spectroscopy. The expanded ESW and superior performance of B MCDE are explained by its high quality material properties and nanostructured, almost nanoporous surface (feature size < 100 nm) formed in the WiS electrolyte. The results reveal that, with a well-controlled quality, boron-doped diamond electrodes provide apparent advantages for water-in-salt SCs.Dataset contains PowerPoint presentation with several images, opj file with the raman data, SEM crossection image and zip with the SEM data.micrographs; cross sections of model simulation or prediction (MSP).扩大水性电解质的电化学稳定窗口（electrochemical stability window, ESW），可提升电化学储能器件与超级电容器（supercapacitors, SC）的能量密度。本工作针对硝酸钠（NaNO₃）盐包水（water-in-salt, WiS）电解质在1~12 m的宽浓度区间内的二电极与三电极体系，采用微波等离子体化学气相沉积（microwave plasma Chemical Vapor Deposition, CVD）制备的掺硼微晶金刚石（boron-doped microcrystalline diamond, B-MCDE，晶粒尺寸约1 μm）作为工作电极，揭示了其独特的电化学相互作用。相较于商用玻碳电极（commercial glassy carbon electrode, C-GCE），该体系可将ESW拓展至约3 V。在10 mHz~100 kHz的频率范围内，针对所有测试的电解质浓度，B-MCDE均展现出优于C-GCE的导电性能（电荷转移电阻Rct低至50 Ω）与电容性能（双电层电容Cdl最高达3.2 μF），并确定了适配的等效电路。在中性pH值与室温条件下，8 m浓度的WiS电解质体系性能最优；而12 m浓度的WiS电解质则不稳定，该结论经拉曼光谱验证。B-MCDE之所以能获得拓展的ESW与更优异的性能，源于其优异的材料本征特性，以及在WiS电解质中形成的纳米结构、近乎纳米多孔的表面（特征尺寸小于100 nm）。研究结果表明，在制备质量可控的前提下，掺硼金刚石电极可显著提升盐包水超级电容器的综合性能。本数据集包含带多幅图像的PowerPoint演示文稿、存储拉曼数据的opj文件、扫描电子显微镜（scanning electron microscopy, SEM）截面图像，以及包含SEM显微照片数据的压缩包；还包含模型模拟与预测（model simulation or prediction, MSP）截面图。