Towards Room Temperature Rechargeable Fluoride-Ion Batteries

自20世纪90年代初索尼推出商用锂离子电池以来，锂离子电池因其高能量密度而成为便携式电子产品的首选电源。LIBS正被缓慢地引入电动汽车(EV)和电网存储应用中。这些高能量密度的LIBS使用富钴或富镍的层状正极材料，这带来了几个问题。为了满足日益增长的需求，迫切需要超越LIBS的高能、可持续和安全的电池技术。氟离子电池(FIB)提供了一种潜在的下一代电化学储能装置，与最先进的LIBS相比，它具有更高的能量密度和安全性。一旦实现其全部潜力，FIB将改变汽车行业和其他能源储存行业，超越LIB。目前，由于使用低氟离子导电固体电解质，FIBS只能在高温下运行。开发合适的液体电解液有可能激发可充电氟离子电池的潜在潜力，控制氟化物在溶液中的反应活性是开发非水液体电解液的关键。早期的缺电子硼络合物被用来结合氟离子并控制其反应活性。然而，含硼分子与氟离子的结合太强，不会将氟离子释放到电化学池中的电极上，因此不适合电解应用。一系列有机分子控制着氟离子在溶液中的反应活性，同时它们会将氟离子释放到电化学池中的电极上(根据结合能预测)。这样的分子将使用于纤维增强塑料的先进液体电解质的开发成为可能。在另一种方法中，PI还建议开发新的“准非水”氟化物输送液体电解质。这两种类型的液体电解液将用于构建和研究各种金属/金属氟化物组合的FIB。本项目的主要目标是开发适合传输氟离子的非水和准非水液体电解液，确保氟离子电池在室温下高能和安全地工作。潜在的应用和好处：该项目的主要成果将促进室温光纤的快速发展，并将为实现高能可充电光纤在便携式电子产品、电网和电动汽车中的应用铺平道路。

Since the commercial introduction of lithium-ion batteries (LIBs) by Sony in the early 1990s, LIBs become preferred power sources in portable electronics due to their high energy density. LIBs are being slowly introduced in the electric vehicles (EVs) and for grid storage applications. These high energy density LIBs use cobalt or nickel-rich layered cathode materials, which pose several issues. To meet the growing demands, high energy, sustainable, and safe battery technologies that are beyond LIBs are urgently required. Fluoride-ion batteries (FIBs) offer a potential next-generation electrochemical energy storage device that has a higher energy density and safety when compared with state-of-the-art LIBs. Upon realization of its full potential, FIBs would transform the automotive sector and other energy storage sectors beyond LIBs. Currently, FIBs are operated at high temperatures limited by the use of low fluoride-ion conducting solid electrolytes. The development of suitable liquid electrolytes has the potential to bring out the hidden potential of rechargeable fluoride-ion batteries.Controlling the reactivity of fluoride in solution is vital to develop non-aqueous liquid electrolytes. Earlier electron-deficient boron complexes were used to bind the fluoride ions and control its reactivity. However, boron-based molecules bind fluoride ions too strongly and will not release the fluoride ions to the electrodes in electrochemical cells; therefore, these complexes are not suitable for electrolytic applications. A series of organic molecules have identified that control the reactivity of the fluoride ions in solution, and at the same time, they would release the fluoride ions to the electrode in electrochemical cells (predicted based on the binding energy). Such molecules will enable the development of advanced liquid electrolytes for FIBs. In an alternative approach, the PI has also proposed to develop new 'quasi non-aqueous' fluoride transporting liquid electrolytes. These two types of liquid electrolytes will be used to build and investigate FIBs with various metal/metal fluoride combinations.The main objectives of the project are to develop suitable fluoride-ion-transporting non-aqueous and quasi-non-aqueous liquid electrolytes and to ensure that fluoride ion batteries perform under room temperature with high energy and safety. Potential applications and benefit: The primary outcome of the project will enable the rapid development of room temperature FIBs and will pave the way for the realisation of high energy rechargeable FIBs with applications in portable electronics, grid, and EVs.