ERI: Molecular-level Characterization of Water-in-Salt Electric Double-Layer Capacitors: Nanoscale Thermal Effects on Differential Capacitance

预计未来几年储能需求将大幅增长。电池是最常见的解决方案，但它们有多个缺点，例如寿命短，低温性能低，火灾/爆炸危险高。新一代超级电容器因其重量轻、充电快、使用安全、无毒等优点而成为很有前途的候选者。预计超级电容器也将满足高能量需求（取代电池），其市场规模预计将在未来六年内增加四倍。然而，设计用于在高电位下工作的新一代纳米多孔超级电容器的热行为还没有得到很好的理解，阻碍了它们的潜在用途。该项目将研究温度的影响，以使超级电容器更可靠，并支持其未来的需求。与此同时，教育活动将在广泛的教育水平上建立纳米技术意识，以吸引学生到科学，技术，工程，和数学（STEM）相关的专业，以支持未来的劳动力，特别是来自查塔努加地区学校的代表性不足的群体。双电层（EDL）电容器（EDLC）是一种很有前途的储能技术，因为电极/电解质界面在非常小的距离处保持大的电势差。这创造了EDLC的主要优势，但也使得精确计算非常具有挑战性。由于分子水平机制在纳米水平上占主导地位，因此EDL的形成以及累积热的传递表现出非连续性行为。利用分子动力学，该项目将提供电极/电解质界面处的EDL形成和纳米级传热的耦合行为的真实表征。该项目的总体目标是描述具有多孔石墨烯的新型盐包水电解质的电容随结构和温度条件的变化。该项目将使用分子水平的建模来探索电极/电解质系统的行为。目标是描述（i）通过电解质域和电解质/电极界面的热传递，（ii）作为所得温度的函数的离子分布，以及（iii）在相应工作条件下的微分电容。“双电层”和“纳米级传热”耦合行为的基础知识将支持从生物医学科学到能源的广泛应用的发展。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Energy storage needs are expected to grow substantially in the coming years. Batteries are the most common solution, but they have multiple downsides, such as short lifetime, low performance at low temperatures, and high fire/explosion hazard risks. New generation supercapacitors are promising candidates owing to their light weight, fast charging, safe use, and non-toxic content. Supercapacitors are expected to satisfy high energy needs as well (to replace batteries) and their market size is expected to increase four times over the next six years. However, the thermal behavior of new generation nanoporous supercapacitors designed to work at high potentials is not well understood, hindering their potential use. This project will investigate the temperature influence to make supercapacitors more reliable and support their transformation for future needs. In parallel, educational activities will create nanotechnology awareness in a wide range of education levels to attract students to the Science, Technology, Engineering, and Math (STEM) related professions to support future workforces especially from underrepresented groups from Chattanooga-area schools.Electric double-layer (EDL) capacitor (EDLC) is a promising technology to store energy since the electrode/electrolyte interface holds a large electric potential difference at a very small distance. This creates the main advantage of EDLCs, but also makes accurate calculations very challenging. The EDL formation as well as transfer of built-up heat shows non-continuum behavior since molecular level mechanisms are dominant at nano-levels. Using molecular dynamics, the project will provide the true characterization of coupled behavior of EDL formation and nanoscale heat transfer at the electrode/electrolyte interface. The overall objective of this project is to describe capacitance of new water-in-salt electrolytes with porous graphene as a function of structural and temperature conditions. The project will use molecular-level modeling to explore the behavior of the electrode/electrolyte systems. Goals are to describe (i) the heat transfer through electrolyte domain and electrolyte/electrode interface, (ii) the ionic distributions as a function of resulting temperatures, and (iii) the differential capacitance at corresponding working conditions. The fundamental knowledge created on the coupled behavior of “electric double layer” and “nanoscale heat transfer” will support the development of a wide range of applications from biomedical science to energy.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.