Shuai Liu, Puiki Leung, Linyang Li, Yong Zuo, Lei Wei, Frank C Walsh, Xun Zhu, Tianshou Zhao, Qiang Liao
Sodium-ion batteries have emerged as a sustainable alternative to lithium-ion batteries, supported by the wide availability and low cost of sodium resources. However, many reported cathodes suffer from low redox potentials, sluggish kinetics, limited cycling stability and temperature sensitivity. Herein, we employed a donor-strength-tuning strategy to design and synthesize an all-donor conjugated polymer cathode, TPPAPZ, via cross-coupling polymerization of a moderate donor (N 1,N 1,N 4,N 4-tetrakis(4-bromophenyl)benzene-1,4-diamine, TPPA-4Br) with a strong donor (5,10-dihydrophenazine, PZ). The combination of two electronically differentiated donor units modulates the frontier electronic structure while maintaining a rigid conjugated backbone, providing a favorable electronic structure for charge transport. The TPPAPZ cathode delivers a high average discharge potential of 3.4 V, exceptional rate capability (128 mAh g-1 at 10 A g-1) and ultra-long cycling stability (50 000 cycles). Notably, it exhibits robust performance across a wide temperature range from -30 °C (118 mAh g-1) to 50 °C (160 mAh g-1). In full cells, TPPAPZ achieves ∼159 mAh g-1. This all-donor polymer design strategy provides a transferable route to mitigate the voltage-capacity trade-off in organic electrodes, enabling the development of long-cycle and wide-temperature sodium dual-ion batteries.