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The insufficient durability of Pt‐based catalysts and the sluggish kinetics of oxygen reduction reaction (ORR) is hampering the development of proton exchange membrane fuel cells (PEMFCs) for commercialization. Herein, a single atom Ti‐modified activated nitrogen‐doped porous carbon (Ti‐a‐NPC) is designed to equalize O2‐activation/*OH‐removal through regulating the charge rearrangement of ultra‐small L12‐Pt3Co for efficient and durable oxygen reduction. The Ti single‐atom modified in the surface/pore of Ti‐a‐NPC can anchor the Pt‐based intermetallic nanoparticles (NPs) not only guarantees Pt‐based intermetallics' ultra‐fine size (≈2.62 nm) but also maintains Pt‐based intermetallics during ORR process. The enhanced catalyst (L12‐Pt3Co/Ti‐a‐NPC) achieves 11‐fold mass activity (1.765 A mgPt−1) compared to commercial Pt/C. Notably, after 30 000 cycles of accelerated durability tests, the mass activity of the L12‐Pt3Co/Ti‐a‐NPC only decreased by 3.7%, while that of commercial Pt/C decreased by 37.1%. Rationalized by theoretical simulation, the introduction of Ti atoms can form charge channels between L12‐Pt3Co NPs and Ti‐a‐NPC, accelerating the charge transfer in the ORR process. Furthermore, the charge of L12‐Pt3Co will accumulate to Ti atoms and buffer the electron transfer of L12‐Pt3Co to the N atoms, thus optimizing the adsorption performance of the active site to the oxygen‐containing intermediate and improving the intrinsic activity of the catalyst. [ABSTRACT FROM AUTHOR]

The Na3V2(PO4)2F3 (NVPF) cathode material is usually nano‐sized particles exhibiting low tap density, high specific surface area, correspondingly low volume energy density, and cycle stability of the sodium‐ion batteries (SIBs). Herein, a high‐temperature shock (HTS) strategy is proposed to synthesize NVPF (HTS‐NVPF) with uniform conducting network and high tap density. During a typical HTS process (heating rate of 1100 °C s−1 for 10 s), the precursors rapidly crystallize and form large‐sized and dense particles. The tight connection between particles not only enhances their contact with carbon layers, but also reduces the specific surface area that inhibits side reactions between the interfaces and the electrolyte. Besides, ultrafast synthesis of NVPF reduces the F loss and amount of Na3V2(PO4)3 impurities, which improve cycling capability. The HTS‐NVPF demonstrates a high energy density of 413.4 Wh kg−1 and an ultra‐high specific capacity of 103.4 mAh g−1 at 10 C as well as 84.2% capacity retention after 1000 cycles. In addition, the excellent temperature adaptability of HTS‐NVPF (−45–55 °C) and remarkable electrochemical properties of NVPF||HC full cell demonstrate extreme competitiveness in commercial SIBs. Therefore, the HTS technique is considered to be a high‐efficiency strategy to synthetize NVPF and is expected to prepare other cathode materials. [ABSTRACT FROM AUTHOR]

Insufficient electrochemical activity and mass transport have been a longstanding issue hindering the development of high‐performance electrode for vanadium redox flow batteries. In this work, vertical‐aligned bismuth‐nanosheets that unlock interfacial dynamics with enhanced catalytic and transport properties are decorated on the electrode surface. The vertical‐aligned structures form highways to guide reactants transport from bulk solution to electrode surface, reducing transport resistance and optimizing active sites utilization. Meanwhile, the bismuth‐nanosheets, dominated by (012) planes with large amounts of unsaturated bismuth atoms, boost the number of electroactive sites and catalytic activity. Full‐cell EIS tests show that the charge transfer resistance and the finite diffusion resistance with prepared electrode are 49.4 and 47.7 mΩ cm−2, 71.3%, and 6.7% lower than those with traditional electrode. In full‐cell tests, the battery delivers a peak power density of 1340 mW cm−2 and achieves an energy efficiency of 85.8% at 200 mA cm−2, which is 4.4% higher than that with traditional electrodes. Remarkably, the battery can maintain an energy efficiency of 82.4% at 300 mA cm−2 and be stably cycled for over 2000 cycles with an only 0.0016% efficiency decay per cycle. This work paves a feasible platform to fabricate advanced electrode for vanadium redox flow batteries. [ABSTRACT FROM AUTHOR]