Enhancing Performance in Polyanionic Cathode Materials

气候变化带来的威胁越来越大，这使得能源储存比以往任何时候都更加重要。锂离子电池(Lib)给便携式电子产品带来了革命性的变化，并对电动汽车产生了越来越大的影响。这一成功归功于它们的高能量密度，这使得小型轻型电池能够为越来越小和复杂的电子设备提供动力。然而，对于电动汽车或静态储能等应用，需要将高能量和功率密度与低成本和高安全性相结合的新一代电池材料。减少二氧化碳排放的需要优先于使用可再生能源，而不是燃烧化石燃料。这些可再生能源的间歇性和供需匹配的需要要求储存高峰生产时产生的过剩能量，以便在需求高峰时释放。电化学储能是解决这一挑战的较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正受到人们的极大关注。与层状过渡金属氧化物相比，聚氧阴离子中氧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。这项工作的目的是研究新的聚阴离子系统，特别是草酸盐，包括加入高电负性的氟，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外，草酸盐基团本身也可能表现出氧化还原行为。通过结合实验和计算技术，我们将能够对这些材料有更全面的了解，并将其开发为可能的应用。为了实现这一点，我们组建了一个强大的合作者团队。这些合作伙伴包括计算(DFT)和实验(穆斯堡尔和X射线吸收光谱)研究的学术伙伴，以及Faradion和Johnson Mattheen的工业支持。我们的方法将最大限度地增加将过渡金属和草酸盐氧化还原结合起来的机会，从而获得更高的容量，而不是传统的纯金属氧化还原活性。

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.