Ni-Doped Cobalt Phosphite, Co11(HPO3)8(OH)6, with Different Morphologies Grown on Ni Foam Hydro(solvo)thermally for High-Performance Supercapacitor

Enriched Fe Doped on Amorphous Shell Enable Crystalline@Amorphous Core-Shell Nanorod Highly Efficient Electrochemical Water Oxidation

The rational design of efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER) with sluggish kinetics, is imperative to diverse clean energy technologies. The performance of electrocatalyst is usually governed by the number of active sites on the surface. Crystalline/amorphous heterostructure has exhibited unique properties and opens new paradigms toward designing electrocatalysts with abundant active sites for improved performance. Hence, Fe doped Ni-Co phosphite (Fe-NiCoHPi) electrocatalyst with cauliflower-like structure, comprising crystalline@amorphous core-shell nanorod, is reported. The experiments uncover that Fe is enriched in the amorphous shell due to the flexibility of the amorphous component. Further density functional theory calculations indicate that the strong electronic interaction between the enriched Fe in the amorphous shell and crystalline core host at the core-shell interface, leads to balanced binding energies of OER intermediates, which is the origin of the catalyst-activity. Eventually, the Fe-NiCoHPi exhibits remarkable activity, with low overpotentials of only 206 and 257 mV at current density of 15 and 100 mA cm-2 . Unceasing durability over 90 h is achieved, which is superior to the effective phosphate electrocatalysts. Although the applications at high current remain challenges , this work provides an approach for designing advanced OER electrocatalysts for sustainable energy devices.

Tetrahedral framework nucleic acid carrying angiogenic peptide prevents bisphosphonate-related osteonecrosis of the jaw by promoting angiogenesis

The significant clinical feature of bisphosphonate-related osteonecrosis of the jaw (BRONJ) is the exposure of the necrotic jaw. Other clinical manifestations include jaw pain, swelling, abscess, and skin fistula, which seriously affect the patients’ life, and there is no radical cure. Thus, new methods need to be found to prevent the occurrence of BRONJ. Here, a novel nanoparticle, tFNA-KLT, was successfully synthesized by us, in which the nanoparticle tetrahedral framework nucleic acid (tFNA) was used for carrying angiogenic peptide, KLT, and then further enhanced angiogenesis. TFNA-KLT possessed the same characteristics as tFNA, such as simple synthesis, stable structure, and good biocompatibility. Meanwhile, tFNA enhanced the stability of KLT and carried more KLT to interact with endothelial cells. First, it was confirmed that tFNA-KLT had the superior angiogenic ability to tFNA and KLT both in vitro and in vivo. Then we apply tFNA-KLT to the prevention of BRONJ. The results showed that tFNA-KLT can effectively prevent the occurrence of BRONJ by accelerating angiogenesis. In summary, the prepared novel nanoparticle, tFNA-KLT, was firstly synthesized by us. It was also firstly confirmed by us that tFNA-KLT significantly enhanced angiogenesis and can effectively prevent the occurrence of BRONJ by accelerating angiogenesis, thus providing a new avenue for the prevention of BRONJ and a new choice for therapeutic angiogenesis.

High Energy Density in Combination with High Cycling Stability in Hybrid Supercapacitors

Hybrid supercapacitors are considered the next-generation energy storage equipment due to their superior performance. In hybrid supercapacitors, battery electrodes need to have large absolute capacities while displaying high cycling stability. However, enhancing areal capacity via decreasing the size of electrode materials results in reductions in cycling stability. To balance the capacity-stability trade-off, rationally designed proper electrode structures are in urgent need and still of great challenge. Here we report a high-capacity and high cycling stability electrode material by developing a nickel phosphate lamination structure with ultrathin nanosheets as building blocks. The nickel phosphate lamination electrode material exhibits a large specific capacity of 473.9 C g^-1 (131.6 mAh g^-1, 1053 F g^-1) at 2.0 A g^-1 and only about 21% capacity loss at 15 A g^-1 (375 C g^-1, 104.2 mAh g^-1, 833.3 F g^-1) in 6.0 M KOH. Furthermore, hybrid supercapacitors are constructed with nickel phosphate lamination and activated carbon (AC), possessing high energy density (42.1 Wh kg^-1 at 160 W kg^-1) as well as long cycle life (almost 100% capacity retention after 1000 cycles and 94% retention after 8000 cycles). The electrochemical performance of the nickel phosphate lamination structure not only is commensurate with the nanostructure or ultrathin materials carefully designed in supercapacitors but also has a longer cycling lifespan than them. The encouraging results show the great potential of this material for energy storage device applications.

Dual modulation of the morphology and electric conductivity of NiCoP on nickel foam by Fe doping as a superior stability electrode for high energy supercapacitors

Nickel-cobalt bimetallic phosphide (NiCoP) is a potential electrode material for supercapacitors on account of its high theoretical specific capacitance. However, its practical application is restricted because of its relatively poor cycling stability and rate performance. Herein, we constructed self-standing NiCoP nanowires and Fe doped NiCoP nanoarrays with different iron ion concentrations on nickel foam (Fe-NiCoP/NF-x%, x = 4, 6.25, 12.5, 25) as a positive electrode for asymmetric supercapacitors (ASCs). The morphological result reveals that the nanostructure of the material evolves from nanowires to nanosheets with the iron doping concentration, and the Fe-NiCoP/NF-12.5% nanosheets possess a more stable structure than NiCoP/NF nanowires. The density functional theory analysis implies that the conductivity of the material enhances after Fe doping because of the increased charge density and electron states. The combination of multicomponents and structural advantages endows the optimal Fe-NiCoP/NF-12.5% electrode with an ultrahigh areal capacitance of 9.93 F cm^-2 (2758.34 F cm^-3) under 1 mA cm^-2, excellent rate capability (82.58% from 1 mA cm^-2 to 50 mA cm^-2) and superior cycling stability (95.72% retention over 5000 cycles under 20 mA cm^-2), and the areal capacitance of Fe-NiCoP/NF-12.5% is 2.27 times higher than that of the pristine NiCoP/NF electrode at 1 mA cm^-2. Moreover, the assembled Fe-NiCoP/NF-12.5%//activated carbon ASC device delivers a high energy density of 0.327 mW h cm^-2 (60.43 mW h cm^-3) at 1.10 mW cm^-2 (202.54 mW cm^-3). Therefore, this strategy may provide a novel route for the application of NiCoP with its intrinsic advantages in the energy storage field.

A triple-layered PPy@NiCo LDH/FeCo2O4 hybrid crystalline structure with high electron conductivity and abundant interfaces for supercapacitors and oxygen evolution

A PPy@NiCo LDH/FeCo₂O₄ triple-layer hybrid with bi-continuous conductive networks is fabricated via a novel one-step hydrothermal reaction and in situ polymerization.

The morphology controlled growth of Co11(HPO3)8(OH)6 on nickel foams for quasi-solid-state supercapacitor applications

Co₁₁(HPO₃)₈(OH)₆ microstructures with different morphologies growing on NF were synthesized under different conditions, and the flower-like sample presents excellent electrochemical properties.

A binder-free Ni2P2O7/Co2P2O7 nanograss array as an efficient cathode for supercapacitors

Binder-free Ni₂P₂O₇/Co₂P₂O₇ cathode of nanograss morphology, delivered an energy and power density of 33.2 W h kg⁻¹ and 257.8 W kg⁻¹ respectively. Through power law, the contribution of each type of mechanism in charge storage process was calculated.

PVP-Assisted Synthesis of Self-Supported Ni2P@Carbon for High-Performance Supercapacitor

Highly conductive and stable electrode materials are usually the focus of high-performance supercapacitors. In this work, a unique design of Ni₂P@carbon self-supported composite nanowires directly grown on Ni foam was applied for a supercapacitor. The Co₃O₄ nanowire array was first synthesized on the Ni foam substrate, and the resulting Ni₂P@carbon nanocomposite was obtained by hydrothermally coating Co₃O₄ with the Ni-ethylene glycol complex followed by gaseous phosphorization. We have discovered that the molecular weight of surfactant polyvinylpyrrolidone (PVP) used in the hydrothermal step, as well as the temperature for phosphorization, played very important roles in determining the electrochemical properties of the samples. Specifically, the sample synthesized using PVP with 10 k molecular weight and phosphorized at 300°C demonstrated the best supercapacitive performance among the different samples, with the highest capacitance and most stable cyclic retention. When an asymmetric supercapacitor (ASC) was assembled with this Ni₂P@carbon sample as the cathode and activated carbon (AC) as the anode, the ASC device showed excellent capacitances of 3.7 and 1.6 F cm⁻² at 2 and 50 mA cm⁻², respectively, and it kept a high capacitance of 1.2 F cm⁻² after 5000 cycles at a current rate of 25 mA cm⁻². In addition, the ASC could reach a high energy density of about 122.8 Wh kg⁻¹ at a power density of 0.15 kW kg⁻¹ and 53.3 Wh kg⁻¹ at the highest power density of 3.78 kW kg⁻¹. Additionally, this device also had the ability to power up 16 red LEDs effortlessly, making it a strong candidate in electrochemical energy storage for practical usage.

F or V-induced activation of (Co, Ni)2P during electrocatalysis for efficient hydrogen evolution reaction

A series of (Co, Ni)₂P–xF and post-(Co, Ni)₂P–xF electrocatalysts with different compositions, morphologies and HER performances were synthesized. Among them, post-(Co, Ni)₂P–10F exhibits the best HER activity.

Novel nickel–cobalt phosphite with face-sharing octahedra derived electrocatalyst for efficient water splitting

Nickel–cobalt phosphite (CoNiPO) including local structural motifs with face-sharing octahedra shows excellent OER activity. The derivatized electrocatalyst (NiP₂@CoNiPO) exhibits high HER activity. DFT calculations indicated the super-exchange effect in CoNiPO can adjust local electronic structure and improve their catalytic activity.