Exploring All-Solid-State Batteries using First-Principles Modelling: Effective Computational Strategies towards Better Batteries

能源储存在当今社会中扮演着比以往任何时候都更重要的角色，已经成为我们这个时代最大的研究挑战之一。英国能源和气候变化部承诺，通过《气候变化法》，到2050年将温室气体排放量减少80%，最近宣布在能源存储研发方面投资2.46亿GB。这些举措的动机是，英国必须从全球向新能源和更有效的存储的过渡中受益。然而，解决当前电池技术中的限制将是英国发展高性能、可持续、低环境影响的能量存储的关键。自20世纪80年代以来，可充电锂离子电池(LIB)开创了清洁有效的能量存储和便携式电子产品革命的先河。同样，LIBS可以成为开发电动汽车和电网规模可再生能源存储的关键技术。然而，由于安全问题，LIBS的升级并不简单。有机电解液--通常用于传统锂离子电池--具有挥发性、易燃性，甚至具有爆炸性，有可能导致灾难性的故障，特别是当大量使用在多电池中为能源密集型应用提供动力时。随着传统锂离子电池接近理论极限，人们对满足苛刻能量需求的新一代电池技术的需求不断增长。全固态电池(ASSB)通过用固体当量取代有机电解液溶液，不仅可以缓解这些安全问题，而且由于其更高的能量密度，还可以提供优异的电池性能。这使得ASSB成为各种行业中具有挑战性的应用的理想选择，无论是小型(芯片上的电池或传感器)、中型(电动汽车)还是大规模(可再生能源的网格级存储)。然而，在ASSB完全商业化之前，仍然需要解决三个主要挫折：(1)与传统电池相比，当前ASSB组件的性能有限；(2)固体电解液和电极之间的化学、电化学和机械不兼容；(3)全球锂储量有限，在对锂离子电池的需求不断增长的同时，增加了电池单位成本。ASSB作为下一代电池的全部潜力可以通过发现具有比当前技术更高的能量密度、更快的充电速度、更安全的操作、更好的组件兼容性和更低的价格等新的电池材料来释放。基于基于实验室的反复试验，实验材料的发现可能既昂贵又耗时：必须在实验室合成并稳定一种新材料，然后才能评估其作为电池组件的效率。计算建模工具可以通过从头开始预测新材料，并提供基于计算机的实验来表征新材料，补充物理实验，从而帮助加速这一反复试验的过程。在这个框架中，该项目的主要目标是通过使用计算模型在原子水平上解决这些主要限制，使用自下而上的方法来改进全固态电池技术。这一目标将通过以下三个目标来实现：(1)发现性能优越的新型ASSB材料，即新的固态电解质和适用于锂离子及锂离子以外(如钠和钾)电池技术的电极。(2)在ASSB中设计更好的固体电解质-电极界面，以增强其机械和电化学稳定性。(3)合理设计超薄膜沉积策略，以覆盖ASSB组件，以增强它们之间的兼容性。

Energy storage has a more central role in our society today than ever before and has become one of the greatest research challenges of our time. The UK's Department of Energy & Climate Change has committed to the green-house gas emission reduction of 80% by 2050 through the Climate Change Act and has recently announced an £246-million investment in energy storage R&D. Such moves are motivated by the necessity for the UK to benefit from what is a global transition to new energy sources and more effective storage. However, solving the limitations in the current battery technologies will be key in order for the UK to develop high-performance, sustainable energy storage with low environmental impact. Since the 1980s, rechargeable Lithium-ion batteries (LIBs) have pioneered clean and effective energy storage and revolutionised portable electronics. Similarly, LIBs can be the key technology for the development of electric vehicles and grid-scale storage of renewable energy. The upscaling of the LIBs is, however, not straightforward due to safety issues. Organic electrolyte solutions -commonly used in the conventional Li-ion batteries- are volatile, flammable and even explosive, potentially causing catastrophic failures, specifically when used in substantial amounts in multi-cell batteries to power energy-intensive applications. As we near the theoretical limits of conventional Li-ion batteries, there is an ever-growing need for next-generation battery technologies that can meet the stringent energy demand.By replacing the organic electrolyte solutions with solid equivalents, all solid-state batteries (ASSB) can not only mitigate these safety issues, but also provide superior battery performances due to their higher energy density. This renders ASSBs ideal for challenging applications in various industries, on a small (battery on a chip or sensor), medium (electric vehicles) to large scale (grid-level storage for renewables). Three major setbacks, however, still need to be addressed before ASSBs can be fully commercialised: (1) the limited performance of the current ASSB components compared to traditional battery ones; (2) chemical, electrochemical and mechanical incompatibilities between the solid electrolytes and electrodes; (3) globally limited Li reserves, increasing the battery unit costs whilst demands for Li-ion batteries are growing.The full potential of ASSBs as next-generation batteries can be unlocked by the discovery of new battery materials with superior features compared to current technology, such as higher energy densities, faster charge rates, safer operation, better component compatibility and lower prices. Based on lab-based trial-and-error, the experimental materials discovery can be both expensive and time consuming: a new material must be synthesised and stabilized in the lab before its efficiency as a battery component can be assessed. Computational modelling tools can help accelerate this trial-and-error process both by predicting novel materials from scratch and by providing computer-based experiments to characterize the novel materials, complementing the physical experiments.In this framework, the main goal of this project is to improve all-solid-state battery technology using a bottom-up approach by tackling these primary limitations at an atomic level using computational modelling. This goal will be achieved by addressing three objectives:(1) To discover novel ASSB materials with superior performance, namely new solid-state electrolytes and suitable electrodes for the Li-ion and beyond Li-ion (e.g. sodium and potassium) battery technologies.(2) To engineer better solid electrolyte-electrode interfaces within ASSBs to augment their mechanical and electrochemical stability.(3) To rationally design ultrathin film deposition strategies to coat ASSB components to augment their compatibility with each other.