Vanadium nitride(VN)-based materials have been investigated as negative electrode materials for supercapacitors(SCs)owing to their high theoretical capacitances and suitable negative potential windows.However,viable V...Vanadium nitride(VN)-based materials have been investigated as negative electrode materials for supercapacitors(SCs)owing to their high theoretical capacitances and suitable negative potential windows.However,viable VNbased negative electrode materials suffer from irreversible electrochemical oxidation of the soluble vanadium species,leading to rapid capacitance fading when operated in aqueous electrolytes.Developing a versatile approach to enhance the stability of VN in aqueous electrolytes is still a challenge.Here,an interface engineering strategy is developed to intentionally introduce surface nanolayers of vanadium oxides(VO_(x))as a reactive template on the VN surface to formulate welldesigned polypyrrole@VNO(Ppy@VNO)core-shell nanowires(NWs)incorporated into a 3D porous N-doped graphene(NG)hybrid aerogel as a durable negative electrode for SCs.Experimental and theoretical investigations reveal that the in-situ constructed Ppy@VNO core-shell host can offer more efficient pathways for rapid electron/ion transport and accessible electroactive sites.Most importantly,a reversible surface redox reaction is realized through the transformation of the valence state of V,and a long cyclic stability is achieved.The Ppy@VNO/NG hybrid aerogel can deliver a high specific capacitance of 650 F g^(-1) at 1 A g^(-1) with approximately 70.7%capacitance retention(up to the twenty-fold current density),and an excellent cycling stability without any capacitance decay after 10,000 cycles at both low and high current densities(1 and 10 A g^(-1),respectively).This work paves the way for the development of advanced electrode materials for SCs.展开更多
基金financially supported by the National Natural Science Foundation of China (52002059 and 51872204)the Belt&Road Young Scientist Exchanges Project of Science and Technology Commission Foundation of Shanghai (20520741000)+3 种基金Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Lowdimension Materials (Donghua University)(18520750400)the Fundamental Research Funds for the Central Universities (20D110631)DHU Distinguished Young Professor Program (LZA2019001)the Open Research Fund of Shanghai Center for High Performance Fibers and Composites and Center for Civil Aviation Composites of Donghua University
文摘Vanadium nitride(VN)-based materials have been investigated as negative electrode materials for supercapacitors(SCs)owing to their high theoretical capacitances and suitable negative potential windows.However,viable VNbased negative electrode materials suffer from irreversible electrochemical oxidation of the soluble vanadium species,leading to rapid capacitance fading when operated in aqueous electrolytes.Developing a versatile approach to enhance the stability of VN in aqueous electrolytes is still a challenge.Here,an interface engineering strategy is developed to intentionally introduce surface nanolayers of vanadium oxides(VO_(x))as a reactive template on the VN surface to formulate welldesigned polypyrrole@VNO(Ppy@VNO)core-shell nanowires(NWs)incorporated into a 3D porous N-doped graphene(NG)hybrid aerogel as a durable negative electrode for SCs.Experimental and theoretical investigations reveal that the in-situ constructed Ppy@VNO core-shell host can offer more efficient pathways for rapid electron/ion transport and accessible electroactive sites.Most importantly,a reversible surface redox reaction is realized through the transformation of the valence state of V,and a long cyclic stability is achieved.The Ppy@VNO/NG hybrid aerogel can deliver a high specific capacitance of 650 F g^(-1) at 1 A g^(-1) with approximately 70.7%capacitance retention(up to the twenty-fold current density),and an excellent cycling stability without any capacitance decay after 10,000 cycles at both low and high current densities(1 and 10 A g^(-1),respectively).This work paves the way for the development of advanced electrode materials for SCs.
