Organic electrode materials hold substantial promise for sodium-ion batteries while suffering from poor electronic conductivity and high solubility in common organic electrolytes. Among various organic electrode materials, π-d conjugated coordination polymers (CCPs) are particularly noteworthy due to their exceptional chemical stability and conductivity, which arise from the hybridization between the d orbitals of metal ions and the π orbitals of organic ligands. Herein, we synthesized a variety of CCPs by utilizing 2,5-dihydroxy-1,4-benzoquinone (DHBQ) as a ligand, with M²⁺ (M = Ni, Co, and Mn) ions serving as metal centers. This approach enabled a thorough investigation into the impact of these metal sites on the electrochemical performance of the CCPs. Theoretical calculations demonstrated that Ni-DHBQ exhibits the smallest bandgap and the highest degree of π-d conjugation compared to its analogs, facilitating the transport of Na⁺ ions. Consequently, Ni-DHBQ delivers the highest capacity (157 mAh g⁻¹ at 0.1 A g⁻¹), enhanced rate ability (153.9 mAh g⁻¹ at 0.2 A g⁻¹), and remarkable cycling stability (capacity retention of 92.9% over 500 cycles at 1 A g⁻¹). Additionally, the reaction mechanism of Ni-DHBQ was comprehensively investigated using in situ x-ray diffraction, complemented by ex situ Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. The results suggest that π-conjugated quinone groups are responsible for the reversible accommodation of Na⁺ ions. This work underscores the significance of metal centers within CCPs, offering critical insights into the molecular-level design of CCPs with enhanced sodium-ion storage capabilities.

Organic redox-active polymers provide promising alternatives to metalcontaining inorganic compounds in Li-ion batteries (LIBs), whereas suffer from low actual capacities, poor rate/power capabilities, and inferior cycling stability. Herein, poly(anthraquinonyl sulfide)-coated carbon nanotubes (CNT@PAQS) are readily performed by in situ polymerization to form core–sheath nanostructures. Remarkably, flower-like PAQS nanosheets are interwoven around CNTs to synergistically create robust 3D hierarchical networks with abundant cavities, internal channels, and sufficiently-exposed surfaces/edges, thereby promoting electron transport and making more active sites accessible for electrolytes and guest ions. Apparently, the asfabricated CNT@PAQS cathode delivers the large reversible capacity (200.5 mAh g⁻¹ at 0.05 A g⁻¹), high-rate capability (161.5 mAh g⁻¹ at 5.0 A g⁻¹), and impressive cycling stability (retaining 88.0% over 1000 cycles). In addition, an asymmetric full-battery using CNT@PAQS as a cathode and cyclized polyacrylonitrile-encapsulated CNTs as an anode is assembled that delivers a high energy density of 86.3 Wh kg⁻¹, and retains 81.3% of initial capacity after 1000 cycles. This work opens up an efficient strategy to combine highly conductive and redox-active phases into core–sheath heterostructures to unlock the barrier of high-rate charge storage. The further integration of two polymer-based electrodes into asymmetric full cells would also consolidate the development of low-cost, sustainable, and powerful batteries.