Locked Coplanar Conformation Boosts Rapid Electron/Ion Transport in Linear Polyimide Cathodes for Sodium‐Ion Storage ^†

Comprehensive Summary Organic materials have obtained unprecedented attention as emerging electrodes for sodium‐ion batteries (SIBs), but they suffer from poor cycling stability and rate performance. Herein, we develop a simple strategy via locking the coplanarity to tune the electron and ion transport in linear polyimide for sodium‐ion batteries. From unlocked and flexible molecular chain to spatially locked molecular chain, the polyimide cathodes possess better structural stability and higher electronic conductivity, exhibiting better cycling stability and higher reversible capacity. Moreover, the locked‐in coplanar conformation endows the polyimide cathode with large surface area and rich porosity, leading to a rapid ion transport, which synergizes with the good electronic conductivity to improve the rate performance of the SIBs. As a result, the optimized polyimide electrode displays high capacity retentions of 99% after 100 cycles at 50 mA·g –1 and 100% after 3000 cycles at 1000 mA·g –1 . This work expands the palette to design organic electrodes for high‐performance SIBs.