Polyoxometalate‐Bridged Synthesis of Superstructured Mesoporous Polymers and Their Derivatives for Sodium–Iodine Batteries

Abstract

Despite the impressive progress in mesoporous materials over past decades, for those precursors having no well‐matched interactions with soft templates, there are still obstacles to be guided for mesoporous structure via soft‐template strategies. Here, a polyoxometalate‐assisted co‐assembly route is proposed for controllable construction of superstructured mesoporous materials by introducing polyoxometalates as bifunctional bridge units, which weakens the self‐nucleation tendency of the precursor through coordination interactions and simultaneously connects the template through the induced dipole–dipole interaction. By this strategy, a series of meso‐structured polymers, featuring highly open radial mesopores and dendritic pore walls composed of continuous interwoven nanosheets can be facilely obtained. Further carbonization gave rise to nitrogen‐doped hierarchical mesoporous carbon decorated uniformly with ultrafine γ‐Mo2N nanoparticles. Density functional theory proves that nitrogen‐doped carbon and γ‐Mo2N can strongly adsorb polyiodide ions, which effectively alleviate polyiodide dissolving in organic electrolytes. Thereby, as the cathode materials for sodium–iodine batteries, the I2‐loaded carbonaceous composite shows a high specific capacity (235 mA h g−1 at 0.5 A g−1), excellent rate performance, and cycle stability. This work will open a new venue for controllable synthesis of new hierarchical mesoporous functional materials, and thus promote their applications toward diverse fields.

Mesoporous Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) as Efficient Iodine Host for High-Performance Zinc–Iodine Batteries

“…56 Among them, after I 3 − adsorption, PEDOT:PSS exhibited a wider energy band distribution shifted to a lower energy level and exhibited a highly active antibonding orbital near 2.02 eV, indicating the high reactivity between I 3 − and PEDOT:PSS. 57 Therefore, as an iodine host, PEDOT:PSS can effectively stabilize soluble I 3 − , ensuring that the battery exhibits a high specific capacity and good cycling ability.…”

“…In addition, the continuous PDOS patterns of PEDOT:PSS-I 2 , PEDOT:PSS-I – , and PEDOT:PSS-I 3 – possess a considerable distribution around the Fermi level, indicating significant orbital hybridization of iodine species with the polymer . Among them, after I 3 – adsorption, PEDOT:PSS exhibited a wider energy band distribution shifted to a lower energy level and exhibited a highly active antibonding orbital near 2.02 eV, indicating the high reactivity between I 3 – and PEDOT:PSS . Therefore, as an iodine host, PEDOT:PSS can effectively stabilize soluble I 3 – , ensuring that the battery exhibits a high specific capacity and good cycling ability.…”

Metal–iodine batteries: achievements, challenges, and future

“…Therefore, when the pore size was reduced to 10–20 nm and γ-Mo 2 N was introduced as a catalyst for iodine conversion, the self-assembled porous materials demonstrated improved battery stability and capacity (213.5 mA h g −1 after 800 cycles at 3.55C). 148 Notably, a novel fully conjugated phthalocyanine copper metal–organic framework (MOF) was introduced into Na–I 2 batteries as the iodine host. The presence of atomically dispersed metal centers, abundant pore structures, and an extended π-conjugation structure makes it an ideal host for iodine.…”