Balance of Ion and Electron Transport in Ferrocene-Based Polymer Organic Cathode for High-Performance Lithium-Ion Batteries

Polymer organic electrodes with unique electron storage and ion storage mechanisms have achieved remarkable development in recent years. However, the specific capacity and rate capability of organic electrodes are still unsatisfactory due to the slow ion and electron transport. Most importantly, some measures used to improve electron or ion transport come at the expense of slowing down the transport of the other. Therefore, achieving a balance between ion and electron transport and accelerating electrode reaction kinetics through underlying molecular design remain a formidable task. Herein, we adopted a measure of combining the rigidity and flexibility of the polymer backbone to realize fast electron and ion transport simultaneously. When the prepared polymer Fc-EDA was used as the cathode for lithium-ion batteries, it provided a high capacity of 160 mA h g^–1 at 0.1 A g^–1, corresponding to an active site utilization of up to 83%. Fc-EDA had excellent rate capability, with the capacities at 2 A g^–1 and 10 A g^–1 being 60% and 40% of that at 0.1 A g^–1, respectively. In addition, it could be cycled over 3500 times at 2 A g^–1 with a capacity retention of 60%.