Galvanic Replacement-Mediated Synthesis of Ni-Supported Pd Nanoparticles with Strong Metal-Support Interaction for Methanol Electro-oxidation.

Herein, well-defined Pd nanoparticles (NPs) developed on Ni substrate (Pd NPs/Ni) are synthesized via a facile galvanic replacement reaction (GRR) route performed in ethaline-based deep eutectic solvent (DES). For comparison, a Pd NPs/Ni composite is also prepared by the GRR method conducted in an aqueous solution. The Pd NPs/Ni obtained from the ethaline-DES is catalytically more active and durable for the methanol electro-oxidation reaction (MOR) than those of the counterpart derived from conventional aqueous solution and commercial Pd/C under alkaline media. Detailed kinetic analysis indicates that the unique solvent environment offered by ethaline plays vital roles in adjusting the reactivity of the active species and their mass transport properties to control over the genesis of the Pd NPs/Ni nanocomposite. The resulting Pd NPs/Ni catalyst possesses a homogeneous dispersion of Pd NPs with a strong Pd (metal)-Ni (support) interaction. This structure enhances the charge transfer between the support and the active phases, and optimizes the adsorption energy of OH- and CO on the surface, leading to superior electrocatalytic performance. This work provides a novel GRR strategy performed in ethaline-DES to the rational design and construction of advanced metal/support catalysts with strong interaction for improving the activity and durability for MOR.

Co-doped NiFe carbonate hydroxide hydrate nanosheets with edge effect constructed from spent lithium-ion battery ternary cathodes for oxygen evolution reaction.

The recycling of spent lithium-ion batteries (LIBs) has received increasing attention for environment and resource reclamation. Converting LIBs wastes into high-efficiency catalysts is a win-win strategy for realizing resource reclamation and addressing sustainable energy challenges. Herein, we developed a simple method to upcycle spent-LIBs cathode powder into Co-doped NiFe carbonate hydroxide hydrate (Co/NFCH-FF) as a low-cost and efficient oxygen evolution reaction (OER) electrocatalyst. The optimized Co/NFCH-FF electrode appears very competitive OER performances with low overpotentials of 201 and 249 mV at 10 and 100 mA cm-2, respectively, a small Tafel slope of 48.4 mV dec-1, and a high long-term stability. Moreover, we reveal that the existence of Co atoms leads to the formation of a crystalline/amorphous (c/a) interface at the Co/NFCH nanosheet edge, inducing the nanosheets possess a unique edge effect to enhance electric fields and accumulate hydroxide ions (OH-) at the edge during the OER process. Benefiting from edge effect, Co/NFCH-FF shows outstanding intrinsic activity. Furthermore, Co atoms as dopants stabilize the electronic structure of Co/NFCH-FF, enabling Co/NFCH-FF to exhibit excellent catalytic stability. This work provides an effective strategy for converting the end-life LIBs to high-performance multicomponent OER electrocatalysts and proposes new insights into the mechanism of enhanced catalytic activity of Co/NFCH.

The multicomponent synergistic effect of a hierarchical Li0.485La0.505TiO3 solid-state electrolyte for dendrite-free lithium-metal batteries.

Development of a composite electrolyte with high ionic conductivity, excellent electrochemical stability and preeminent mechanical strength is beneficial for suppressing Li-dendrite penetration and unstable interfacial reactions in solid-state Li-metal batteries. Herein, a novel composite electrolyte material comprising perovskite Li0.485La0.505TiO3 (LLTO), poly(ethylene oxide) (PEO), and a barium titanate (BTO)-polyimide (PI) composite matrix has been successfully fabricated. Benefiting from the well-defined ion channels, the resulting BTO-PI@LLTO-PEO-FEC-LiTFSI (BP@LPFL) exhibits excellent cycling stability, low interfacial resistance, enhanced mechanical strength, and high ionic conductivity. Particularly, BP@LPFL possesses an excellent ionic conductivity of 3.0 × 10-4 S cm-1 at room temperature and achieves a wide electrochemical window of 5.2 V (vs. Li+/Li). For Li-LiFePO4 batteries, such an ingenious structure yields a discharge capacity of 124 mA h g-1 at 0.1 C after 200 cycles at room temperature and delivers a discharge capacity of 165 mA h g-1 at 0.1 C after 110 cycles at 60 °C. Additionally, the symmetric Li cell remains stable after 700 h at a current density of 0.5 mA cm-2. Furthermore, ex situ X-ray photoelectron spectroscopy and ex situ scanning electron microscopy were used to verify the interface evolution. Besides, a flexible full battery is fabricated, which exhibits impressive performance. These properties presented here provide support for BP@LPFL as a feasible candidate electrolyte for solid-state lithium batteries.

Deep eutectic solvent-assisted in-situ synthesis of nanosheet-packed Ni3S2 porous spheres on Ni foam for high-performance supercapacitors.

Herein, self-supported Ni3S2 spherical clusters packed with well-defined nanosheets developed on Ni foam (NF) were rationally fabricated via a novel low-temperature solvothermal sulfurization approach in a choline chloride/ethylene glycol (Ethaline)-based deep eutectic solvent (DES). The DES-based sulfurization process drove an interesting time-dependent surface restructuring and phase transformation that occurred on the Ni substrate, leading to the in-situ formation of a Ni3S2 layer with controllable architecture. Pre-deposition of a Ni interlayer on the NF substrate provides more assessable electrochemical surface area and reaction sites, which favored fast crystal nucleation/growth and structural reconstruction. Benefiting from the integrated design and unique 3D interdigital architecture, the optimized Ni3S2_5/Ni/NF with a sulfurization time of 5 h exhibits a high specific capacitance (specific capacity) of 5,633 mF cm-2 (860.6 µAh cm-2) at a current density of 10 mA cm-2, and maintains 87.7% of initial specific capacitance after 1,000 charge-discharge process at a current density of 20 mA cm-2. This facile DES-driven solvothermal sulfurization strategy for the fabrication of integrated metal sulfides-based electrode materials could be promising for practical applications in high-performance electrochemical devices.