Computational modelling of energy materials

开发应用于可充电电池、超级电容器、太阳能电池和光催化剂的先进材料是加速采用可再生能源技术的关键。利用量子力学预测材料结构和性能的第一性原理方法在该领域的材料发现和优化中发挥着越来越重要的作用。然而，真实的材料并不完美。它们通常是纳米级结构，并包含一系列影响性能的扩展缺陷（如晶界）。本项目旨在发展和应用主要基于密度泛函理论（DFT）的理论方法来模拟一系列多晶能源材料中扩展缺陷的结构、热力学和电子特性，以了解它们对性能的影响并指导材料的优化。该项目的初始阶段（第一年）将重点了解钛酸钡（BTO）薄膜中晶粒边界的作用，该薄膜与多层超级电容器相关，可用于移动电子设备和个人计算机的高效片上储能。特别是，BTO中晶界（GB）缺陷的结构和电子特性[特别是（111）和（310）GB]将使用DFT和伽马表面方法进行研究，如小组先前的工作所述[例如K. P. McKenna, ACS Energy Letters 3, 2663(2018)]。由于GB缺陷的存在以及相关的固有点缺陷（如空位）的偏析，电子性质的调制将被研究。该项目还将研究铁电极化对GB性能的影响。将与实验合作者密切互动，以测试预测和验证结果。M. Nafria（巴塞罗那大学）和G. Bersuker（美国航空航天公司）的团队将在多晶BTO薄膜上提供实验导电AFM映射，以与理论预测进行比较。在第二和第三年，学生将在第一学年的经验、方法和技能的基础上，建立其他能源材料的晶界模型，再次与实验合作者密切互动，以测试预测和验证结果。我们计划与利物浦大学的K. Durose、Jon Major和Tim Veal合作，研究晶界对下一代太阳能吸收材料（Sb2Se3及相关材料）重组的影响，以及晶界在限制氟掺杂氧化锡（一种广泛用于光伏应用的透明导体）迁移率中的作用。我们将在项目中保留一些灵活性，以处理热门话题的新兴材料，特别是当有新的实验数据可用时，可以通过建模扩展缺陷来更好地理解。

The development of advanced materials for applications in rechargeable batteries, supercapacitors, solar cells and photocatalysts is the key to accelerating the uptake of renewable energy technologies. First principles methods that predict the structure and properties of materials using quantum mechanics are playing an increasingly important role in materials discovery and optimisation in this field. However, real materials are not perfect. They are often structured at the nanoscale and contain a range of extended defects (such as grain boundaries) which affect performance. This project aims to develop and apply theoretical approaches mainly based on density functional theory (DFT) to model the structural, thermodynamic and electronic properties of extended defects in a range of polycrystalline energy materials in order to understand their impact on performance and guide the optimisation of materials.The initial stage of the project (year 1) will focus on understanding the role of grain boundaries in barium titanate (BTO) thin films with relevance to multilayer supercapacitors which find application for efficient on-chip energy storage for mobile electronics and personal computers. In particular, the structure and electronic properties of grain boundary (GB) defects in BTO [specifically (111) and (310) GBs] will be investigated using DFT and the gamma surface method as described in previous work in the group [e.g. K. P. McKenna, ACS Energy Letters 3, 2663 (2018)]. The modulation of electronic properties due to the presence of GB defects as well as associated segregation of intrinsic point defect such as vacancies will be studied. The project will also investigate the role that ferroelectric polarisation plays on GB properties. There will be close interaction with experimental collaborators to test predictions and validate results. The groups of M. Nafria (University of Barcelona) and G. Bersuker (Aerospace Corp., USA) will provide experimental conductive AFM mapping on polycrystalline BTO films to compare to the theoretical predictions.In years 2 and 3 the student will build on the experience, methods and skills developed in year 1 to model grain boundaries in other energy materials, again with close interaction with experimental collaborators to test predictions and validate results. We plan to study the effect of grain boundaries on recombination in next generation solar absorber materials (Sb2Se3 and related materials) in collaboration with K. Durose, Jon Major and Tim Veal (University of Liverpool) and the role of grain boundaries in limiting mobility in fluorine doped tin oxide, a widely used transparent conductor for photovoltaics applications. We will retain some flexibility in the project to tackle emerging materials of topical interest particularly where there new experimental data becomes available that could be better understood by modelling extended defects.