Enhancing Performance in Polyanionic Cathode Materials

气候变化带来的日益严重的威胁使能源储存比以往任何时候都更加重要。锂离子电池（LIB）已经彻底改变了便携式电子产品，并在电动汽车中产生了越来越大的影响。这种成功是由于它们的高能量密度，这使得小型轻电池能够为越来越小和复杂的电子设备供电。然而，需要新一代电池材料，其将高能量和功率密度与低成本和高安全性相结合，用于诸如电动车辆或静态能量存储的应用。减少二氧化碳排放的需要优先考虑使用可再生能源，而不是燃烧化石燃料。这些可再生能源的间歇性以及使供应与需求相匹配的需要要求储存在高峰生产时产生的多余能源，以便在高峰需求时释放。电化学能量存储代表了应对这一挑战的更有吸引力的解决方案之一。多氧阴离子化合物作为传统氧化物的替代阴极受到相当大的关注。与层状过渡金属氧化物相比，氧在聚氧阴离子中的强结合增强了稳定性，从而提高了安全性，并通过感应效应提高了电压。本工作的目的是研究新的聚阴离子体系，特别是聚阴离子盐，包括引入高电负性的氟，这有利于改善电化学性能和提高电压。在一个特别令人兴奋的发展中，我们的初步研究表明，除了传统的过渡金属氧化还原活性，草酸盐基团本身可能表现出氧化还原行为。通过采用实验和计算技术的结合，我们将能够对这些材料获得更全面的了解，并将其推向可能的应用。为了实现为此，我们组建了一个强大的合作者团队。其中包括计算（DFT）和实验（穆斯堡尔和X射线吸收光谱）研究的学术合作伙伴，以及Faradion和约翰逊万丰的工业支持。我们的方法将最大限度地利用联合收割机结合过渡金属和草酸盐氧化还原的机会，从而获得更高的容量，超越传统的仅金属氧化还原活性。

The increasing threat posed by climate change has made energy storage more important than ever before. Lithium-ion batteries (LIB) have revolutionised portable electronics and have growing impact in electric vehicles. This success is due to their high energy densities which permit small light batteries to power increasingly small and complicated electronic devices. However, new generations of battery materials are required which combine high energy and power densities with low cost and high safety, for applications such as electric vehicles or static energy storage. The need to reduce CO2 emissions prioritises the use of renewable energy sources as opposed to the burning of fossil fuels. The intermittent nature of these renewable energy sources and the need to match supply with demand requires the storage of excess energy generated at peak production so that it may be released at times of peak demand. Electrochemical energy storage represents one of the more attractive solutions to this challenge. Polyoxyanion compounds are receiving considerable interest as alternative cathodes to conventional oxides. The strong binding of the oxygen in polyoxyanions enhances stability and thus safety, compared with layered transition metal oxides and raises the voltage via the inductive effect. The aim of this work is to investigate new polyanion systems, particularly oxalates, including the incorporation of highly electronegative fluorine which is beneficial for improving the electrochemical performance and raising the voltage.In a particularly exciting development, our preliminary studies indicate that in addition to conventional transition metal redox activity, the oxalate group itself may show redox behaviour.By employing a combination of experimental and computational techniques we will be able to obtain a fuller understanding of these materials and develop them towards possible application.In order to achieve this we have assembled a strong team of collaborators. These include academic partners for both computational (DFT) and experimental (Mossbauer and X-ray absorption spectroscopy) studies, together with industrial support from Faradion and Johnson Matthey.Our approach will maximise the opportunity to combine transition metal and oxalate redox and thereby obtain higher capacities, beyond the conventional metal-only redox activity.