Minakshi Manickam, Mujeeb Agha, Whale Jonathan, Evans Richard, Aughterson Rob, Shinde Pragati A, Ariga Katsuhiko, Shrestha Lok Kumar
Engineering and Energy, Murdoch University, WA, 6150, Australia.
Sustainable Futures, MIRRECO, Perth, WA, 6000, Australia.
Chempluschem. 2024 Dec;89(12):e202400408. doi: 10.1002/cplu.202400408. Epub 2024 Oct 23.
Energy storage in electrochemical hybrid capacitors involves fast faradaic reactions such as an intercalation, or redox process occurring at a solid electrode surface at an appropriate potential. Hybrid sodium-ion electrochemical capacitors bring the advantages of both the high specific power of capacitors and the high specific energy of batteries, where activated carbon serves as a critical electrode material. The charge storage in activated carbon arises from an adsorption process rather than a redox reaction and is an electrical double-layer capacitor. Advanced carbon materials with interconnecting porous structures possessing high surface area and high conductivity are the prerequisites 1128to qualify for efficient energy storage. Herein, we have demonstrated that a porous honeycomb structure activated carbon derived from Australian hemp hurd (Cannabis sativa L.) in aqueous NaSO electrolyte showed a specific capacitance of 240 F/g at 1 A/g. The mass ratio of biochar to KOH during the chemical activation associated with the synthesis temperature influences the change in morphologies, and distribution of pore sizes on the adsorption of ions. At higher synthesis temperatures, the tubular form of the honeycomb starts to disintegrate. The hybrid sodium-ion device employing hemp-derived activated carbon (HAC) coupled with electrolytic manganese dioxide (EMD) in an aqueous NaSO electrolyte showed a specific capacitance of 95 F/g at 1 A/g having a capacitance retention of 90 %. The hybrid device (HAC||EMD) can possess excellent electrochemical performance metrics, having a high energy density of 38 Wh/kg at a power density of 761 W/kg. Overall, this study provides insights into the influence of the activation temperature and the KOH impregnation ratio on morphology, porosity distribution, and the activated carbon's electrochemical properties with faster kinetics. The high cell voltage for the device is devoted to the EMD electrode.
电化学混合电容器中的能量存储涉及快速的法拉第反应，例如在适当电位下在固体电极表面发生的嵌入或氧化还原过程。混合钠离子电化学电容器兼具电容器的高比功率和电池的高比能量的优点，其中活性炭是关键的电极材料。活性炭中的电荷存储源于吸附过程而非氧化还原反应，属于双电层电容器。具有高表面积和高导电性的相互连接的多孔结构的先进碳材料是实现高效能量存储的先决条件。在此，我们证明了在水性NaSO电解质中，由澳大利亚大麻茎髓（大麻）衍生的多孔蜂窝结构活性炭在1 A/g时的比电容为240 F/g。化学活化过程中生物炭与KOH的质量比以及合成温度会影响形态变化以及孔径分布对离子吸附的影响。在较高的合成温度下，蜂窝状的管状结构开始解体。在水性NaSO电解质中，采用大麻衍生的活性炭（HAC）与电解二氧化锰（EMD）耦合的混合钠离子器件在1 A/g时的比电容为95 F/g，电容保持率为90%。混合器件（HAC||EMD）可具有出色的电化学性能指标，在功率密度为761 W/kg时具有38 Wh/kg的高能量密度。总体而言，本研究深入探讨了活化温度和KOH浸渍比对形态、孔隙率分布以及活性炭电化学性能（具有更快的动力学）的影响。该器件的高电池电压归因于EMD电极。
