Flexible Polyimide Derived Anode Material with Stable and High‐Capacity Performance for Next‐Generation Lithium‐Ion Batteries

The lithium (Li) battery industry is constantly evolving, thanks to the introduction of novel materials, particularly anode materials, which contribute to the stability, capacity, and cyclability of the battery. This continuous development has led to the development of organic electrodes that are promising for their high capacity, tunable structure, and eco‐friendly properties. However, challenges such as rapid capacity decay and poor cycle stability limit their practical usage. To provide solution for such issues, a novel multicarbonyl‐based organic anode material, polyimide benzoquinone (PIBQ), which shows low solubility in conventional electrolytes and excellent Li storage performance, is reported. It delivers a high initial capacity of ≈823 mAh g ⁻¹ and retains ≈530 mAh g ⁻¹ after 450 cycles at 0.5C, with 64% capacity retention and nearly 100% coulombic efficiency (C.E.). In addition, the PIBQ cell shows an initial capacity of ≈645 mAh g ⁻¹ at 1C displaying a unique self‐stabilizing capacity behavior, increasing to ≈520 mAh g ⁻¹ after 530 cycles and stable for 1000 cycles with capacity retention of ≈80% and ≈100% C.E. Experimental results show that the electrode exhibits a dominant pseudocapacitive charge storage behavior, especially within the testing potential window (93.5% at 1 mV s ⁻¹ ), enabling fast charge kinetics. Density functional theory analysis shows that PIBQ's smaller highest occupied molecular orbital–lowest unoccupied molecular orbital gap contributes to enhance the energy storage capability.