Zinc–iodine batteries are
promising energy storage
devices
with the unique features of aqueous electrolytes and safer zinc. However,
their performances are still limited by the polyiodide shuttle and
the unclear redox mechanism of iodine species. Herein, a single iron
atom was embedded in porous carbon with the atomic bridging structure
of metal–nitrogen–carbon to not only enhance the confinement
effect but also invoke the electrocatalytic redox conversion of iodine,
thereby enabling the large capacity and good cycling stability of
the zinc–iodine battery. In addition to the physical trapping
effect of porous carbon with good electronic conductivity, the in
situ experimental characterization and theoretical calculation reveal
that the metal–nitrogen–carbon bridging structure modulates
the electronic properties of carbon and adjusts the intrinsic activity
for the reversible conversion of iodine via the thermodynamically
favorable pathway. This work demonstrates that the physicochemical
confinement effect can be invoked by the rational anchoring of a single
metal atom with nitrogen in a porous carbon matrix to enhance the
electrocatalytic redox conversion of iodine, which is crucial to fabricating
high-performing zinc–iodine batteries and beyond by applying
the fundamental principles.
An atomic bridging structure of nickel–nitrogen–carbon active sites confined in porous carbon was revealed by Jintao Zhang and co‐workers in their Research Article (e202113918). Uncovering the fundamental mechanism reveals a high potential for modulating bridging structures to enhance interfacial electrocatalytic reactions beyond carbon dioxide reduction.
To meet strategic applications, electrochemical reduction of CO 2 into value-added chemical molecules would be improved by the rational design of advanced electrocatalysts with atomically dispersed active sites. Herein an electrospun-pyrolysis cooperative strategy is presented to not only modulate the porous structure of the carbon support for favorable charge and mass transfer, but also adjust the bridging structure of atomically dispersed metal species. Typically, the experimental results and theoretical calculations revealed that the unique chemical structure of binuclear nickel bridging with nitrogen and carbon atoms (namely Ni 2 À N 4 À C 2 ) tunes the electronic nature of the d-states for the optimal adsorption of carbon dioxide and intermediates, thus inducing the substantial enhancement of CO 2 reduction via the thermodynamically more favorable pathway. The identification of such a structure demonstrates the large space to modulate the atomic bridging status for optimizing electrocatalysis.
Interfacial coordination of tannic acid with metal ions enables conformal coating on nickel hydroxide nanowalls for enhancing the water-splitting performance.
Cu2S is considered as a promising electrode material for lithium‐ion and sodium‐ion batteries owing to its flat charge‐discharge plateau as well as the abundant reserves. However, serious capacity fading and formation of polysulfides during electrochemical process restrict its practical application. In this work, a new type of Cu2S@N, S dual‐doped carbon matrix (Cu2S@NSCm) hybrid is synthesized through a simple in‐situ polymerization process and subsequent carbonization process. Due to the N, S dual‐doped carbon matrix, which can buffer the volume change, restrain the dissolution of polysulfide and enhance the electron conductivity during electrochemical process, the hybrid demonstrates excellent electrochemical performance. The Cu2S@NSCm hybrid exhibits a reversible capacity of 560.1 mAh g−1 at a current density of 1000 mA g−1 after 550 cycles when used in lithium‐ion batteries, which is among the best performance for Cu2S based anode materials. Moreover, a capacity of 182.3 mAh g−1 is obtained after 50 cycles when used as an anode material in sodium ion batteries, which is much better than the pure Cu2S.
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