Hong Jindui, Chen Chunping, Siriviriyanun Ampornphan, Crivoi Dana-Georgiana, Holdway Philip, Buffet Jean-Charles, O'Hare Dermot
Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
SCG Chemicals Co., Ltd. 1 Siam Cement Rd, Bangsue Bangkok 10800 Thailand.
RSC Adv. 2021 Aug 10;11(44):27267-27275. doi: 10.1039/d1ra04681k. eCollection 2021 Aug 9.
The development of future mobility ( electric vehicles) requires supercapacitors with high voltage and high energy density. Conventional active carbon-based supercapacitors have almost reached their limit of energy density which is still far below the desired performance. Advanced materials, particularly metal hydroxides/oxides with tailored structure are promising supercapacitor electrodes to push the limit of energy density. To date, research has largely focused on evaluation of these materials in aqueous electrolyte, while this may enable high specific capacitance, it results in low working voltage window and poor cycle stability. Herein, we report the development of NiMn-layered double oxides (NiMn-LDOs) as mixed metal oxide-based supercapacitor electrodes for use in an organic electrolyte. NiMn-LDO obtained by calcination of NiMn(OH)·HO at 400 °C produced the best performing NiMn-LDOs with high working voltage of 2.5 V and a specific capacitance of 44 F g (at 1 A g). We believe the performance of the NiMn-LDOs is related to its unique porous structure, high surface area and the homogeneous mixed metal oxide network. NiMn-LDO outperforms both the single metal oxides (NiO, MnO) and the equivalent physical mixture of the two oxides. We propose this performance boost arises from synergy between NiO and MnO due to a more effective homogeneous network of NiO/MnO domains in the NiMn-LDO. This work clearly shows the advantage of an LDO over the single component metal oxides as well as the physical mixture of mixed metal oxides and highlights the possibilities of development of further mixed metal oxides-based supercapacitors in organic electrolyte using LDH precursors.
未来移动出行（电动汽车）的发展需要具有高电压和高能量密度的超级电容器。传统的活性炭基超级电容器几乎已达到其能量密度极限，而该极限仍远低于预期性能。先进材料，特别是具有定制结构的金属氢氧化物/氧化物，是有望突破能量密度极限的超级电容器电极。迄今为止，研究主要集中在评估这些材料在水性电解质中的性能，虽然这可能会实现高比电容，但会导致工作电压窗口窄和循环稳定性差。在此，我们报告了作为混合金属氧化物基超级电容器电极的镍锰层状双氧化物（NiMn-LDOs）在有机电解质中的开发情况。通过在400℃煅烧NiMn(OH)·HO获得的NiMn-LDO产生了性能最佳的NiMn-LDOs，其工作电压为2.5V，比电容为44F g（在1A g时）。我们认为NiMn-LDOs的性能与其独特的多孔结构、高表面积和均匀的混合金属氧化物网络有关。NiMn-LDOs的性能优于单一金属氧化物（NiO、MnO）以及这两种氧化物的等效物理混合物。我们认为这种性能提升源于NiO和MnO之间的协同作用，这是由于NiMn-LDO中更有效的NiO/MnO域均匀网络。这项工作清楚地展示了层状双氧化物相对于单组分金属氧化物以及混合金属氧化物物理混合物的优势，并突出了使用层状双氢氧化物前驱体在有机电解质中开发进一步的混合金属氧化物基超级电容器的可能性。
