分子辅助制备富含高价态Co3+的三维蜂窝状钴硫化物网络结构用于高性能固态不对称超级电容器

过渡金属氧化态调控工程是一种很有前景的改善电极材料的氧化还原活性、增加活性位点的策略.本文提出了一种简单的三乙醇胺辅助自模板法,制备了一种由交错钴硫化物纳米片(Co_xS_y-T NSs)组装而成的独特的三维蜂窝状网络结构.有趣的是,我们首次发现在该体系中,三乙醇胺可以有效地增加目标产物中的高价态Co³⁺的比例.Co_xS_y-T NSs电极具有高含量的Co³⁺和三维网络结构,使得其在5 A g^-1的电流密度下表现出351 mA h g^-1(2635 F g^-1)的最大比容量和优异的循环稳定性.此外,由Co_xS_y-T NSs和活性炭(AC)电极组装的固态不对称超级电容器在0.81 kW kg^-1功率密度下展现出81.62 W h kg^-1的高能量密度和卓越的长周期循环稳定性,7000次循环后仍有96.2%的容量保持率.该结果证明同时调控高价态的金属物种并构筑三维网络结构是一种简单而有效的制备用于能源存储与转换的高活性电极材料的策略.

Molecule-assisted modulation of the high-valence Co3+in 3D honeycomb-like CoxSynetworks for high-performance solid-state asymmetric supercapacitors

Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensional(3D)honeycomb-like cobalt sulfide(Co_xS_y)network organized by cross-linked nanosheets(Co_xS_y-T NSs)was prepared via a simple triethanolamine(TEOA)-assisted self-templating strategy.Interestingly,it has been found for the first time that the introduction of TEOA in the reaction effectively increases the ratio of high-valence Co³⁺in the final product.Benefiting from the synergetic effect of the tailored high-valence Co³⁺with the 3D network structure,the Co_xS_y-T NS electrode exhibits a maximum specific capacity of 351 mA h g^-1(2635 F g^-1)at 5 A g^-1as well as excellent cycling stability.Furthermore,with the solid-state asymmetric supercapacitor(ASC)constructed based on the Co_xS_y-T NSs and activated carbon(AC)electrodes,a high energy density up to 81.62 W h kg^-1has been achieved at the power density of 0.81 kW kg^-1and 96.2%capacitance is preserved after 7000 cycles,indicating robust cycling stability.This result highlights the simple approach of simultaneously tailoring highvalence metal species and constructing 3D network structure toward high-performance electrode materials for energy storage and conversion.