Electrophoretic Deposition of Ternary Metal Sulfide Electrochemical Electrodes with Tunable Pore Structure

该补助金支持为储能应用的三元金属硫化物电化学电极的制造提供新知识的研究。复杂金属硫化物是由硫与一种以上金属化合而成的材料。这些复杂的金属硫化物已经成为一种新的和越来越多的研究系统，用于能源应用，由于其高应用性能，低成本，和地球丰富的，无毒的标准材料的替代品组合。与目前使用的金属氧化物相比，金属硫化物已表现出更好的导电性、更大的机械和热稳定性以及更高的性能。然而，由金属硫化物纳米结构制成的电极的广泛工业集成（这是大多数能源应用的基础）受到缺乏低成本、高效和简单的大规模生产方法的阻碍。 此外，电极的重要但经常被忽视的设计参数之一是孔结构，其在提高性能方面起着重要作用。这项资助通过研究复杂金属硫化物纳米晶体的可扩展纳米制造方法并将其组装成最佳多孔电极结构来解决这两个问题。这项拨款的结果有利于美国经济和社会，因为电化学电极是电池和超级电容器的关键部件，为现代社会的许多设备和应用提供动力和储存能量。这项工作推动了下一代电化学能源材料的发展，从而改善了能量转换，储存和降低成本。目前的注入法合成三元硫化物纳米晶存在转化率低、重现性差等问题，本项目克服了这些技术障碍，采用无溶剂合成方法，采用高活性阴离子前驱体，如硫化铵，和有机相中的金属羧酸盐。 本研究使用电泳沉积法将复杂金属硫化物纳米晶体组装成具有可控孔隙率的电化学电极。所述纳米结构单元尺寸均匀，并且不使用添加剂，这允许定制和量化电极的填充和孔结构。该研究小组试图通过电场中胶体颗粒的定向组装来实现具有可调孔径的薄三维电极膜的高保真打印。该研究调查了非线性施加的电位，并通过电化学阻抗谱、Voronoi镶嵌法（用于量化孔结构）和径向分布函数分析等方法对薄膜进行表征。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant supports research that contributes new knowledge to the manufacturing of ternary metal sulfide electrochemical electrodes for energy storage applications. Complex metal sulfides are materials made from sulfur combined with more than one metal. These complex metal sulfides have emerged as a new and increasingly researched system for energy applications due to their high application performance, low cost, and portfolio of earth-abundant, non-toxic alternatives to standard materials. Compared to the currently used metal oxides, metal sulfides have demonstrated better electrical conductivity, greater mechanical and thermal stability, and higher performance. However, the widespread industrial integration of electrodes, which is the basis for most energy applications, made from metal sulfide nanostructures is impeded by the lack of large-scale production methods that are low cost, efficient, and simple. Additionally, one of the important but often overlooked design parameters for electrodes is the pore structure, which plays an important role in increasing performance. This grant addresses both issues by investigating methods for scalable nanomanufacturing of complex metal sulfide nanocrystals and assembling them into optimum porous electrode structures. The outcome of this grant benefits the U.S. economy and society because electrochemical electrodes are key components of batteries and supercapacitors, which power and store energy for many devices and applications in modern society. This work advances the next generation of electrochemical energy materials, leading to improvements in energy conversion, storage, and lowering of cost. It broadens the participation of underrepresented groups and promotes teaching and learning by developing lending library modules.Current injection methods for synthesis of ternary sulfide nanocrystals suffers from low conversion yield and poor reproducibility This project overcomes these technical barriers by manufacturing ternary sulfide nanocrystals through a solvent-less synthesis method, employing highly reactive anion precursors, such as ammonium sulfide, and metal carboxylates in the organic phase. This research uses electrophoretic deposition to assemble the complex metal sulfide nanocrystals into electrochemical electrodes with controlled porosity. The nanocrystal building-blocks are uniform in size and no additives are used, which permits tailoring and quantification of the packing and pore structure of the electrode. The research team seeks to achieve high-fidelity printing of thin three-dimensional electrode films with tunable pore size by directed assembly of colloidal particles in electric fields. The research investigates non-linear applied potentials and characterizes the films with methods including electrochemical impedance spectroscopy, Voronoi tessellations to quantify the pore structure, and radial distribution function analysis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.