Two-dimensional mesoporous vanadium phosphate nanosheets through liquid crystal templating method toward supercapacitor application
Two-dimensional mesoporous vanadium phosphate nanosheets through liquid crystal templating method toward supercapacitor application
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DOI：
10.1016/j.nanoen.2018.07.052
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发表时间：
2018-10-01
期刊：
影响因子：
17.6
通讯作者：
Yamauchi, Yusuke
中科院分区：
文献类型：
--
作者：
Mei, Peng;Kaneti, Yusuf Valentino;Yamauchi, Yusuke
本文首次采用易复制的溶致液晶（LLC）模板法成功合成了介孔磷酸钒（VOPO4）纳米片。用三嵌段共聚物（P123）作为表面活性剂，可以得到具有良好的二维六边形介面结构的VOPO4前驱体。通过煅烧完全去除模板后，获得了具有较少有序介观结构的结晶VOPO4框架。制备的介孔voo4纳米片具有优异的赝电容性能（在0.5A g（-1）时达到767 F g(-1)），这是由于其良好的介孔结构产生了丰富的易于接近的氧化还原活性位点以及增强的电荷转移和离子扩散特性。实验证明，介孔voo4纳米片的电荷存储机制是基于酸性介质中V(V)和V（III）之间可逆的两步氧化还原反应。这种有利的LLC模板策略有望为设计各种具有优异电化学性能的介孔金属磷酸盐开辟新的途径，用于储能器件。
Mesoporous vanadium phosphate (VOPO4) nanosheets have been successfully synthesized through an easy and reproducible lyotropic liquid crystals (LLC) templating approach for the first time. Using the triblock copolymer (P123) as a surfactant, VOPO4 precursor with a well-developed 2D hexagonal mesostructure can be obtained. Following complete removal of the template by calcination, crystallized VOPO4 frameworks with less-ordered mesostructure are achieved. The as-prepared mesoporous VOPO4 nanosheets exhibit superior pseudocapacitive performance (767 F g(-1) at 0.5A g(-1)) by virtue of the favorable mesostructure that gives rise to abundant easily accessible redox active sites as well as reinforced charge transfer and ion diffusion properties. The charge storage mechanism of the mesoporous VOPO4 nanosheets has been experimentally demonstrated to be based on the reversible two-step redox reactions between V(V) and V(III) in acidic medium. This advantageous LLC templating strategy is expected to open up a new route for designing various mesoporous metal phosphates with superior electrochemical performance for utilization in energy storage devices.