Ferrocene-Based Polymer Organic Cathode for Extreme Fast Charging Lithium-Ion Batteries with Ultralong Lifespans

To meet the growing demand for energy storage, lithium-ion batteries (LIBs) with fast charging capabilities has emerged as a critical technology. The electrode materials affect the rate performance significantly. Organic electrodes with structural flexibility support fast lithium-ion transport and are considered promising candidates for fast-charging LIBs. However, it is a challenge to create organic electrodes that can cycle steadily and reach high energy density in a few minutes. To solve this issue, accelerating the transport of electrons and lithium ions in the electrode is the key. Here, it is demonstrated that a ferrocene-based polymer electrode (Fc-SO₃Li) can be used as a fast-charging organic electrode for LIBs. Thanks to its molecular architecture, LIBs with Fc-SO₃Li show exceptional cycling stability (99.99% capacity retention after 10 000 cycles) and reach an energy density of 183 Wh kg^-1 in 72 seconds. Moreover, the composite material through in situ polymerization with Fc-SO₃Li and 50 wt % carbon nanotube (denoted as Fc-SO₃Li-CNT50) achieved optimized electron and ion transport pathways. After 10 000 cycles at a high current density of 50C, it delivered a high energy density of 304 Wh kg^-1. This study provides valuable insights into designing cathode materials for LIBs that combine high power and ultralong cycle life.