Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites ...Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites of bulk LDHs increase the internal resistance and reduce the capacity and oxygen-production efficiency of electrodes.Herein,we prepared a polyaniline-coated Ni-Co-layered double hydroxide intercalated with MoO_(4)^(2−)(M-LDH@PANI)composite electrode using a two-step method.As the amount of MoO_(4)^(2−)in the LDH increases,acicular microspheres steadily evolve into flaky microspheres with a high surface area,providing more active electrochemical sites.Moreover,the amorphous PANI coating of M-LDH boosts the electronic conductivity of the composite electrode.Accordingly,the M-LDH@PANI at an appropriate level of MoO_(4)^(2−)exhibits significantly enhanced energy storage and catalytic performance.Experimental analyses and theoretical calculations reveal that a small amount of MoO_(4)^(2−)is conducive to the expansion of LDH interlayer spacing,while an excessive amount of MoO_(4)^(2−)combines with the H atoms of LDH,thus competing with OH^(−),resulting in reduced electrochemical performance.Moreover,M-LDH flaky microspheres can efficiently modulate deprotonation energy,greatly accelerating surface redox reactions.This study provides an explanation for an unconventional mechanism,and a method for the modification of LDH-based materials for anion intercalation.展开更多
文摘Low-overpotential layered hydroxides(LDHs)with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction;however,the low electronic conductivity and insufficient active sites of bulk LDHs increase the internal resistance and reduce the capacity and oxygen-production efficiency of electrodes.Herein,we prepared a polyaniline-coated Ni-Co-layered double hydroxide intercalated with MoO_(4)^(2−)(M-LDH@PANI)composite electrode using a two-step method.As the amount of MoO_(4)^(2−)in the LDH increases,acicular microspheres steadily evolve into flaky microspheres with a high surface area,providing more active electrochemical sites.Moreover,the amorphous PANI coating of M-LDH boosts the electronic conductivity of the composite electrode.Accordingly,the M-LDH@PANI at an appropriate level of MoO_(4)^(2−)exhibits significantly enhanced energy storage and catalytic performance.Experimental analyses and theoretical calculations reveal that a small amount of MoO_(4)^(2−)is conducive to the expansion of LDH interlayer spacing,while an excessive amount of MoO_(4)^(2−)combines with the H atoms of LDH,thus competing with OH^(−),resulting in reduced electrochemical performance.Moreover,M-LDH flaky microspheres can efficiently modulate deprotonation energy,greatly accelerating surface redox reactions.This study provides an explanation for an unconventional mechanism,and a method for the modification of LDH-based materials for anion intercalation.
