Qingzhong Xue

Lithium‐iodine batteries are hindered by the polyiodide shuttle effect, where conventional mitigation strategies face a fundamental trade‐off between active material confinement and redox reversibility. Herein, we report a monolithic host‐separator continuum that address this dilemma through spatially organized compartmentalization. The architecture integrates an oxidized sulfonated lignin‐functionalized graphene aerogel (GA@SOL) core with an encapsulating sulfonated cellulose polymer (SCP) shell via sequential infiltration and freeze‐drying, minimizing the interfacial discontinuities inherent in stacked configurations. Within the conductive scaffold, iodine adsorption spontaneously generates a mixed‐valence iodine species (I ⁻ /I ₂ /I ₃ ⁻ ) via balanced Lewis acid‐base interactions, establishing a redox‐active environment that preserves electronic connectivity without compromising reaction kinetics. Concurrently, the sulfonate‐rich SCP shell establishes an electrostatic Donnan barrier that selectively repels polyiodide anions while facilitating Li ⁺ transport. The resulting GA@SOL‐I ₂ @SCP cathode delivers 252 mAh g ⁻¹ at 1 C with 89.6% retention over 1500 cycles, a Li ⁺ transference number of 0.63, and mitigated self‐discharge (76.1% capacity retention after 120 h). Operando spectroscopy and in situ impedance monitoring confirm sustained polyiodide accessibility and suppressed anode corrosion. This work demonstrates that structural continuity and mixed‐valence‐enabled charge transport can decouple confinement from kinetic penalty, offering a design framework for conversion‐type energy storage systems plagued by soluble intermediates.

Tailoring the coordination geometry of metal centers through polymorphism offers a powerful approach to isolating the structural origin of catalytic activity in metal–organic frameworks (MOFs). Herein, two copper-pyrazolate (Pz) polymorphs, α-Cu(Pz)₂ and β-Cu(Pz)₂ were synthesized, featuring identical chemical compositions and 1-periodic chain structures but distinct local coordination configurations. Remarkably, the β-Cu(Pz)₂ exhibits a faradaic efficiency (FE) of 93.33% for the nitrate reduction reaction (NO₃RR), significantly outperforming α-Cu(Pz)₂ (53.10%). Comprehensive structural analyses, in situ spectroscopy, and density functional theory (DFT) calculations revealed that the coordination geometry governs the electronic structure of the Cu active centers. Specifically, the cis-configured β-Cu(Pz)₂ enables more delocalized Cu 3d orbitals and stronger Cu–O (NO₃ ⁻) electronic coupling, thereby promoting nitrate adsorption and activation. This work demonstrates that MOF polymorphism allows precise tuning of electronic structures, offering a fundamental design principle for the development of advanced electrocatalysts toward sustainable nitrogen-cycle chemistry.

The imperative for reliable lithium batteries under extreme low-temperature (LT) conditions has revived interest in organic electrodes, yet their practical deployment is frustrated by severe electrode dissolution and sluggish Li⁺ desolvation kinetics. Here, we uncover solvent concentration polarization between the electric double layer (EDL) and bulk electrolyte as a hitherto-overlooked but decisive degradation mechanism. This polarization reshapes the EDL into a solvent-rich domain, elevating the desolvation barrier and amplifying solvent-electrode interactions that exacerbate dissolution. Guided by this insight, we engineer a highly depolarized solvent that suppresses EDL solvent aggregation and restructures the solvation structure from solvent-dominated to anion-enriched. The resulting electrolyte achieves an exceptional ionic conductivity of 0.51 mS cm⁻¹ at −60 ^oC and a high Li⁺ transference number of 0.65, while fostering a robust, inorganic-rich electrode|electrolyte interphase that mitigates dissolution. Consequently, even at −60 ^oC, the Li||DSR (Disodium rhodizonate) cell affords an outstanding capacity of 184.3 mAh g⁻¹ and remarkable cycling stability over 2000 cycles with an ultralow decay rate of only 0.0057% per cycle. This strategy proves generalizable to other organic electrodes, establishing the combating of solvent concentration polarization as a guiding principle for ultrafast-cycling and long-life lithium batteries under extreme LT conditions.

A series of π–d conjugated copper anilate coordination polymers incorporating different halogen atoms (F, Cl, and Br) were synthesized, with the halogen type significantly affecting the NO ₃ RR performance.

Prussian blue (PB) is one of the main cathode materials with industrial prospects for the sodium ion battery. The structural stability of PB materials is directly associated with the presence of crystal water within the open 3D framework. However, there remains a lack of consensus regarding whether all forms of crystal water have detrimental effects on the structural stability of the PB materials. Currently, it is widely accepted that interstitial water is the stability troublemaker, whereas the role of coordination water remains elusive. In this work, the dynamic evolution of PB structures is investigated during the crystal water (in all forms) removal process through a variety of online monitoring techniques. It can be inferred that the PB-130 °C retains trace coordination water (1.3%) and original structural integrity, whereas PB-180 °C eliminates almost all of crystal water (∼12.1%, including both interstitial and coordinated water), but inevitably suffers from structural collapse. This is mainly because the coordinated water within the PB material plays a crucial role in maintaining structural stability via forming the -N≡C-Fe^LS-C≡N- conjugate bridge. Consequently, PB-130 °C with trace coordination water delivers superior reversible capacity (113.6 mAh g^-1), high rate capability (charge to >80% capacity in 3 min), and long cycling stability (only 0.012% fading per cycle), demonstrating its promising prospect in practical applications.