沥青基活性炭-MnO复合材料的可控制备及其在非对称超级电容器中的应用

Controllable Preparation of Activated Asphalt-Based Carbon-MnO Co mposites and Its Application in Asymmetric Supercapacitors

本研究提供一种适用于超级电容器的沥青基活性炭-MnO复合材料。以石油沥青为碳源,乙酸锰为锰源,通过压片成型和一步活化法的结合,制备得到了MnO负载沥青基活性炭复合材料(PAC@MnO)。PAC@MnO具有高比表面积且孔道主要由微-介多级孔构成。作为电容器电极材料,在三电极体系下,研究了不同MnO负载量对PAC@MnO-x电极性能的影响,其中PAC@MnO-0.3电极在0.5 A/g电流密度下比电容高达344.5 F/g,在高电流密度为20.0 A/g下,仍具有190 F/g的比电容,表现出优异的倍率性能。将PAC@MnO-0.3与PAC@MnO-0组装成水系非对称超级电容器,在5.0 A/g电流密度下循环3 000圈后,其容量保持率高达87.24%,表现出优异的循环稳定性。MnO纳米粒子与PAC的均匀复合不仅显著提升了MnO的导电性,同时抑制了其在充放电过程中的体积膨胀,使PAC@MnO呈现出优异的电化学特性。此外,PAC丰富的多级孔结构为电解液离子的存储提供了大量的活性位点,并为电解液离子的快速传输提供通道。

A pitch-based activated carbon/MnO composite material suitable for supercapacitors is presented.The MnO-loaded pitch-based activated carbon composite materials(PAC@MnO)were prepared via a combination of compression molding and one-step activation method using petroleum pitch as the source of carbon and manganese acetate as the source of manganese.The PAC@MnO composite materials had a high specific surface area,and their pores were mainly composed of micro-mesoporous pores.As an electrode material for supercapacitors,the effect of different MnO loading amounts on the performance of PAC@MnO composite electrodes was studied in a three-electrode system.Among them,the PAC@MnO-0.3 electrode exhibited a specific capacitance of 344.5 F/g at the current density of 0.5 A/g.A high capacitance of 190 F/g could still be afforded by it even at a high current density of 20.0 A/g,demonstrating an excellent rate performance.The asymmetric supercapacitor configured with PAC@MnO-0.3 anode and PAC@MnO-0 cathode delivered a capacitance retention of 87.24%at a high current density of 5.0 A/g after 3000 cycles,reflecting a good cycling stability.The uniform combination of MnO nanoparticles and PAC significantly improves the electrical conductivity of MnO and suppresses its volume expansion during the charging and discharging processes,contributing to the excellent electrochemical properties of PAC@MnO composite materials.In addition,the abundant hierarchical pore structure of PAC provides many active sites for the storage of electrolyte ions and channels for the rapid transport of electrolyte ions.