Design of a Scalable Dendritic Copper@Ni2+, Zn2+ Cation-Substituted Cobalt Carbonate Hydroxide Electrode for Efficient Energy Storage

Robust and Corrosion-Resistant Overall Water Splitting Electrode Enabled by Additive Manufacturing

Electrolysis of water has emerged as a prominent area of research in recent years. As a promising catalyst support, copper foam is widely investigated for electrolytic water, yet the insufficient mechanical strength and corrosion resistance render it less suitable for harsh working conditions. To exploit high-performance catalyst supports, various metal supports are comprehensively evaluated, and Ti6Al4V (Ti64) support exhibited outstanding compression and corrosion resistance. With this in mind, a 3D porous Ti64 catalyst support is fabricated using the selective laser sintering (SLM) 3D printing technology, and a conductive layer of nickel (Ni) is coated to increase the electrical conductivity and facilitate the deposition of catalysts. Subsequently, Co0.8Ni0.2(CO3)0.5(OH)·0.11H2O (CoNiCH) nanoneedles are deposited. The resulting porous Ti64/Ni/CoNiCH electrode displayed an impressive performance in the oxygen evolution reaction (OER) and reached 30 mA cm-2 at an overpotential of only 200 mV. Remarkably, even after being compressed at 15.04 MPa, no obvious structural deformation is observed, and the attenuation of its catalytic efficiency is negligible. Based on the computational analysis, the CoNiCH catalyst demonstrated superior catalytic activity at the Ni site in comparison to the Co site. Furthermore, the electrode reached 30 mA cm-2 at 1.75 V in full water splitting conditions and showed no significant performance degradation even after 60 h of continuous operation. This study presents an innovative approach to robust and corrosion-resistant catalyst design.

Controlled preparation of cobalt carbonate hydroxide@nickel aluminum layered double hydroxide core-shell heterostructure for advanced supercapacitors

Herein, we report the rational fabrication of unique core-shell nanoclusters composed of cobalt carbonate hydroxide (Co-CH) @ nickel aluminum layered double hydroxide (NiAl-LDH) on a carbon cloth (CC) substrate using a two-step hydrothermal strategy. The one-dimensional (1D) Co-CH nanowires core-shell functions as a framework for the growth of two-dimensional (2D) NiAl-LDH nanosheets, leading to the formation of a hierarchically porous core-shell heterostructure. The presence of abundant heterointerfaces enhances electrical conductivity, reduces charge transfer resistance, and facilitates ion/electron transfer. Taking full advantage of its unique nanostructure and synergistic effect of two components, the as-prepared Co-CH@NiAl-LDH hybrid material illustrates a specific capacity of 1029.4 C/g (2058.9 mC cm-2) at 1 A g-1 and good rate capability with a capacity retention of 68.5% at 20 A g-1. Additionally, the assembled Co-CH@NiAl-LDH//pine pollen-derived porous carbon (PPC) hybrid supercapacitor (HSC) delivers impressive energy and power densities of 66.2 Wh kg-1 (0.27 Wh cm-2) and 17529.7 Wh kg-1 (0.11 Wh cm-2), respectively. This device also achieves a superior capacity retention of 80.3% over 20,000 cycles. These findings prove the importance of engineering heterointerfaces in heterostructure for the promotion of energy storage performance.

Self-templated flower-like NiCoZn-carbonate hydroxide hollow nanospheres for asymmetric supercapacitors with high performance

With the increasing demand for energy resources, it is crucial to explore electrode materials with high specific capacitance and cycling stability for supercapacitors. Herein, flower-like NiCoZn-carbonate hydroxide (NiCoZn-CH) hollow nanospheres are prepared using self-templated NiCoZn-glycerate solid nanospheres through the Kirkendall effect in a solvothermal reaction. Benefiting from a flower-like morphology, NiCoZn-CH not only provides large contact areas on the electrolyte-electrode and an abundant number of active sites but also shortens the ion transportation pathway. Meanwhile, the hollow structure also improves cycling stability by relieving stresses. Furthermore, Zn2+ can accelerate the ion transfer and improve the electrochemical activity. Therefore, the Ni1Co1Zn0.25-CH electrode shows an attractive specific capacitance of 1585.2 F g-1 at 1 A g-1 and excellent cycling stability. Additionally, the asymmetric supercapacitor Ni1Co1Zn0.25-CH//AC delivers a superior cycling stability of 99.9% after 15 000 cycles at 10 A g-1 and an energy density of 33.7 W h kg-1 at a power density of 400 W kg-1. This work provides a simple and efficient route for the fabrication of various carbonate hydroxides.

New nickel-rich ternary carbonate hydroxide two-dimensional porous sheets for high-performance aqueous asymmetric supercapattery

Transition metal carbonate hydroxides (M-CHs) are promising candidates for electrode materials in supercapattery, due to their low-cost preparation and high-energy features. However, they also suffer from ionic kinetics bottlenecks without efficient morphological design. Tailoring the chemical compositions and nanostructures of electrode materials to realize high performance is significant for meeting the current demand for electrical energy storage devices. Therefore, we present a simple hydrothermal method for constructing better electrochemically active M-CHs with ternary metal components and hierarchical nanostructures that are assembled by interwoven nanosheets. Benefiting from higher contents of Ni species and superior two-dimensional/three-dimensional (2D/3D) pore structures, the fabricated cobalt-nickel-zinc carbonate hydroxides with Co/Ni/Zn molar ratios of 2:3:1 (CoNiZn-231) delivered the best specific capacity of 1130.8 C g^-1 at 1 A g^-1, decent rate performance (67.2% in 1-10 A g^-1), and excellent cycling performance (92.6% over 10,000 cycles) in comparison with the majority of mono/bimetallic materials. Then, an alkaline hybrid (CoNiZn-231//activated carbon (AC)) device is developed, which shows a high energy density of 31.62 Wh kg^-1 at a power density of 646 W kg^-1 and an excellent capacity retention of 99.27% after 10,000 cycles. Herein, the rational design of trimetallic compositions and hierarchical structures of carbonate hydroxides is described, which provides good choices for the synthesis of high-performance electrode materials in electrochemical energy storage applications.

Heterostructured Co-NTC@Co3S4 as an anode material for asymmetric pseudocapacitors

Herein, a composite structure of ZIF-67@Co-NTC was synthesized and it was partially vulcanized to form layer-like Co3S4 nanosheets to finally successfully synthesize a composite heterostructure of Co-NTC@Co3S4.