Altering electronic structure of nickel foam supported CoNi-based oxide through Al ions modulation for efficient oxygen evolution reaction.

Developing highly active and durable non-precious metal-based electrocatalysts for the oxygen evolution reaction (OER) is crucial in achieving efficient energy conversion. Herein, we reported a CoNiAl0.5O/NF nanofilament that exhibits higher OER activity than previously reported IrO2-based catalysts in alkaline solution. The as-synthesized CoNiAl0.5O/NF catalyst demonstrates a low overpotential of 230 mV at a current density of 100 mA cm-2, indicating its high catalytic efficiency. Furthermore, the catalyst exhibits a Tafel slope of 26 mV dec-1, suggesting favorable reaction kinetics. The CoNiAl0.5O/NF catalyst exhibits impressive stability, ensuring its potential for practical applications. Detailed characterizations reveal that the enhanced activity of CoNiAl0.5O/NF can be attributed to the electronic modulation achieved through Al3+ incorporation, which promotes the emergence of higher-valence Ni metal, facilitating nanofilament formation and improving mass transport and charge transfer processes. The synergistic effect between nanofilaments and porous nickel foam (NF) substrate significantly enhances the electrical conductivity of this catalyst material. This study highlights the significance of electronic structures for improving the activity of cost-effective and non-precious metal-based electrocatalysts for the OER.

N/O Dual-Doped Environment-Friendly Hard Carbon as Advanced Anode for Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) are considered as promising candidates for lithium-ion batteries due to the abundant reserve and lower cost of K resources. However, K+ exhibits a larger radius than that of Li+, which may impede the intercalation of K+ into the electrode, thus resulting in poor cycling stability of PIBs. Here, an N/O dual-doped hard carbon (NOHC) is constructed by carbonizing the renewable piths of sorghum stalks. As a PIB anode, NOHC presents a high reversible capacity (304.6 mAh g-1 at 0.1 A g-1 after 100 cycles) and superior cycling stability (189.5 mAh g-1 at 1 A g-1 after 5000 cycles). The impressive electrochemical performances can be ascribed to the super-stable porous structure, expanded interlayer space, and N/O dual-doping. More importantly, the NOHC can be prepared in large scale in a concise way, showing great potential for commercialization applications. This work may impel the development of low-cost and sustainable carbon-based materials for PIBs and other advanced energy storage devices.