Dual-ion pre-inserted Mo glycerate template for constructing NiMo-OS core–shell structure with boosting performance in zinc ions hybrid supercapacitors

Zinc ion hybrid supercapacitors(ZHS)have received much attention due to the enhanced potential window range and high specific capacity.However,the appropriate positive materials with high electrochemical performance are still a challenge.Herein,NH_(4)^(+)and glycerate anions pre-inserted Mo glycerate(N-MoG)spheres are synthesized and serve as the template to form NH_(4)^(+)intercalated Ni_(3)S_(2)/Ni_(3)O_(2)(OH)_(4)@MoS_(2)core–shell nanoflower(N-NiMo-OS)in-situ grown on nickel foam(NF)(N-NiMo-OS/NF)by sulfurization treatment.Compared with the product using traditional MoG as a template,N-NiMo-OS/NF inheriting a larger core structure from N-MoG delivers enhanced space for ions transport and volume expansion during the energy storage process,together with the synergistic effects of multi-components and the heterostructure,the as-prepared N-NiMo-OS/NF nanoflower exhibits excellent performance for the battery-type hybrid supercapacitors(BHS)and ZHS devices.Notably,the ZHS device delivers superior electrochemical performance to the BHS device,such as a higher specific capacity of 327.5 mAh·g^(−1)at 1 A·g^(−1),a preeminent energy density of 610.6 Wh·kg^(−1)at 1710 W·kg^(−1),long cycle life.The in-situ Raman,ex-situ X-ray photoelectron spectroscopy(XPS),theoretical calculation demonstrate the extra Zn^(2+)insertion/extraction storage mechanism provides enhanced electrochemical performance for ZHS device.Therefore,the dual-ion pre-inserted strategy can be extended for other advanced electrode materials in energy storage fields.

Super-Capacitive Performances of Nickel Foam Supported CeO_2 Nanoparticles

This paper designs and fabricates CeO_2 nanoparticles on a large scale by hydrolysis and oxidation of cerium carbide.The electrochemical supercapacitor behavior of CeO_2 nanoparticles was investigated.The nickel foam(NF) supported CeO_2 nanoparticles show a high areal capacitance of 119 mF/cm^2,demonstrating a strong synergistic effect between NF and CeO_2 nanoparticles.The high capacitance of the CeO_2/NF nanoparticles is possibly due to an improved conductivity by NF and a better utilization of CeO_2 nanoparticles.

明胶填充泡沫Ni并负载NiCo_(2)O_(4)纳米阵列电极的制备及超级电容性能

通过使用明胶凝胶生物质填充再在空气中煅烧实现对泡沫镍冗余空隙的有效填充,再采用水热法在填充后的泡沫镍上原位生长NiCo_(2)O_(4)纳米阵列直接用作免粘合剂的自支撑超级电容器电极材料。借助SEM电镜、Raman光谱及XRD对获得的电极材料进行形貌、结构及物相表征,测试该电极材料的循环伏安、恒电流充放电和交流阻抗等电化学性能。实验结果表明,在三电极体系中以2 mol·L^(-1)KOH溶液作电解质,该电极材料的比容量达到25714 F·m^(-2);当电流密度从10 A·m^(-2)增加到200 A·m^(-2)时,其比容量保持约58.3%,倍率性能良好;在200 A·m^(-2)电流密度下充放电循环2000次后其比容量保留率高达109.3%,表现出优良的循环稳定性。

Boosting charge transfer via interface charge reconstruction between amorphous NiFe-LDH and crystalline NiCo_(2)O_(4)for efficient alkaline water/seawater oxidation

Electrocatalysts with optimal efficiency and durability for the oxygen evolution reaction(OER)are becoming increasingly important as the demand for alkaline water/seawater electrolysis technology grows.Herein,a novel rose-shaped NiFe-layered double hydroxide(LDH)/NiCo_(2)O_(4)composed of amorphous wrinkled NiFe-LDH and highly crystalline NiCo_(2)O_(4)was synthesized with rich heterointerfaces.Many unsaturated metal sites are generated due to significant charge reconstruction at the heterointerface between the crystalline and amorphous phases.These metal sites could trigger and provide more active sites.The density functional theory(DFT)reveals that a new charge transfer channel(Co-Fe)was formed at the heterointerface between NiFe-LDH as electron acceptor and NiCo_(2)O_(4)as electron donor.The new charge transfer channel boosts interfacial charge transfer and enhances catalytic efficiency.The NiFe-LDH/NiCo_(2)O_(4)/nickel foam(NF)drives current densities of 10 and 100 mA·cm−2 with overpotentials of 193 and 236 mV,respectively.The composite electrode demonstrates a fast turnover frequency(0.0143 s−1)at 1.45 V vs.RHE(RHE=reversible hydrogen electrode),which is 5.5 times greater than pure NiCo_(2)O_(4),suggesting its superior intrinsic activity.Additionally,NiFe-LDH/NiCo_(2)O_(4)/NF electrode exhibited negligible degradation after 150 h of uninterrupted running in alkaline seawater oxidation.This study introduces a method for preparing high-efficiency electrocatalysts utilized in alkaline water/seawater electrolysis.