Disordered rocksalt cathode materials for Na-ion Batteries

钠离子电池用无序岩盐正极材料

• 批准号: 2730040
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2730040
• 关键词: Disordered; rocksalt; cathode; materials; Na

Disordered rocksalt cathode materials for Na-ion BatteriesThere is a pressing need to develop rechargeable batteries that are cheaper and more sustainable than the Li-ion battery. Na-ion offers an attractive alternative, but this technology falls short of Li-ion on performance, particularly energy density, due to a lack of suitable high energy Na-ion cathode materials. The key challenges are related to the fact that Na+ ions are larger than Li+. The increased size of Na+ induces changes in the host structure that are much more severe than Li+ when the ions are removed and reinserted, leading to degradation over cycling. There is also a limit to the amount of Na+ that can be incorporated into layered transition metal oxide hosts when they are synthesised, as they are too large to be substituted into sites in the transition metal layers. This means that the best cathodes typically only utilise a fraction of the Na+ ions that may be possible, thus restricting the energy density.This project aims to investigate a new class of Na-ion cathodes based on the disordered rocksalt crystal structure, following the recent discovery of several highly promising Li-ion analogues. The disordered nature of this structure permits the constraints on Na content to be relaxed, unlocking the possibility of synthesising "Na-rich" compositions with the potential to achieve higher energy densities than current state-of-the-art cathodes. The disordered rocksalt structure has also been shown to exhibit much less pronounced structural change during the charge-discharge reaction than in layered phases, allowing stable cycling over much wider compositional ranges. To make these phases, a range of synthetic approaches will be employed including mechanochemical ball-milling, in-situ electrochemical preparation and ion exchange. To understand the chemical and structural changes taking place during cycling, a range of advanced characterisation techniques will be employed, including diffraction, electron microscopy and spectroscopy. Diamond Light Source and ISIS neutron and muon source along with other international research facilities will also be used as part of this research to provide insight into the structural and electronic properties of these materials. The specific PhD thesis aims are: 1) to identify, synthesise and characterise new Na-ion disordered rocksalt compositions based on earth abundant elements, 2) to define the limits of synthetic viability of disordered rocksalt phases, 3) to develop a comprehensive understanding of the chemical and structural stability of these materials during charge and discharge in Na-ion cells, 4) to identify and optimise promising candidates for commercialisation in partnership with Faradion.This project falls within the EPSRC Energy Storage, Electrochemical Sciences and Materials for Energy applications research areas. It is part-funded by Faradion, the UK-based non-aqueous sodium-ion cell technology company.This is a 3.5-year EPSRC DTP-CASE studentship in association with Faradion Ltd.

无序的岩石阴极材料用于Na-ion Batteriest Here，这是一种紧迫的需求，需要开发比锂离子电池更便宜，更可持续的可充电电池。 Na-ion提供了一种有吸引力的替代方案，但是由于缺乏合适的高能量NA-ION阴极材料，该技术的性能（尤其是能量密度）的含量不足。主要挑战与Na+离子大于Li+的事实有关。当离子被去除和重新插入时，Na+的大小增加会引起宿主结构的变化，而宿主结构的变化比LI+更严重，从而导致循环降解。合成后，可以将Na+的量限制在分层的过渡金属氧化物宿主中，因为它们太大，无法将其取代为过渡金属层中的位点。这意味着最好的阴极通常仅利用可能可能发生的Na+离子的一部分，从而限制了能量密度。此项目旨在研究基于无序的岩石晶体结构的新型Na-ion阴极，此前几种非常有希望的Li-iromogues是根据无序的岩石晶体结构进行的。该结构的无序性质允许对NA含量的约束放松，从而释放了合成“富含Na的”成分的可能性，具有比当前最先进的阴极相比获得更高的能量密度的潜力。与分层相比，在电荷分离反应期间，无序的岩石结构在电荷分离反应过程中表现出明显的结构变化的意义要少得多，从而使稳定的循环在较宽的组成范围内稳定。为了使这些阶段进行这些阶段，将采用一系列合成方法，包括机械化学球，原位电化学制剂和离子交换。为了了解骑自行车期间发生的化学和结构变化，将采用一系列高级表征技术，包括衍射，电子显微镜和光谱。 Diamond Light Source和ISIS中子和MUON源以及其他国际研究设施也将用作本研究的一部分，以洞悉这些材料的结构和电子特性。具体的PHD论文的目的是：1）识别，合成和表征基于地球丰富元素的新的Na-Ion无序岩石组成的组成，2）定义无序岩石岩相的合成可行性的局限性，3）以在Na-iros细胞中的化学和排放量中的整体理解，以在Na-ion细胞中识别这些材料的全面理解，并在Na-iros中的整体化中进行了良好的理解，4）法拉第。该项目属于EPSRC的储能，电化学科学和能源应用研究领域的材料。它是由英国的非钠离子细胞技术公司Faradion资助的部分资金。