Rechargeable lithium-ion batteries with high energy density that can be safely charged and discharged at high rates are desirable for electrified transportation and other applications 1-3. However, the sub-optimal intercalation potentials of current anodes result in a trade-off between energy density, power and safety. Here we report that disordered rock salt 4,5 Li3+xV2O5 can be used as a fast-charging anode that can reversibly cycle two lithium ions at an average voltage of about 0.6 volts versus a Li/Li + reference electrode. The increased potential compared to graphite 6,7 reduces the likelihood of lithium metal plating if proper charging controls are used, alleviating a major safety concern (short-circuiting related to Li dendrite growth). In addition, a lithium-ion battery with a disordered rock salt Li3V2O5 anode yields a cell voltage much higher than does a battery using a commercial fastcharging lithium titanate anode or other intercalation anode candidates (Li3VO4 and LiV0.5Ti0.5S2) 8,9. Further, disordered rock salt Li3V2O5 can perform over 1,000 charge-discharge cycles with negligible capacity decay and exhibits exceptional rate capability, delivering over 40 per cent of its capacity in 20 seconds. We attribute the low voltage and high rate capability of disordered rock salt Li3V2O5 to a redistributive lithium intercalation mechanism with low energy barriers revealed via ab initio calculations. This low-potential, high-rate intercalation reaction can be used to identify other metal oxide anodes for fast-charging, long-life lithium-ion batteries.
Structurally ordered intermetallic phases have exhibited higher and higher electrocatalytic activity and stability than disordered alloys in many reactions such as the oxygen reduction reaction (ORR) and small-molecule (hydrogen, formic acid, or ethanol) oxidation reactions. The enhanced electrocatalytic activity could be derived from the definite composition and predictable control over structural, geometric, and electronic effects. This review, based on the understanding of the catalytic mechanism of structurally ordered intermetallic nanoparticles, provides a comprehensive acknowledgment of how the particle size and morphology affect the catalytic performance. The strategy for reducing particle size and the impact of particle size on electrocatalysis will be first introduced. Then, recent developments in the synthesis and design of morphology-controlled catalysts are summarized. The structure−activity relationship between the catalytic activity and morphology including core−shell/hollow and porosity will be highlighted. Finally, the current challenges and future developments are provided. On the basis of this review, intermetallic nanoparticles will shed light on the future development of electrocatalysts for fuel cells and metal-air batteries.
All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na3PS4−xOx, where 0 < x ≤ 0.60) that not only exhibit the highest critical current density among all Na-ion conducting sulfide-based SEs, but also enable high-performance ambient-temperature sodium-sulfur batteries. By forming bridging oxygen units, the Na3PS4−xOx SEs undergo pressure-induced sintering at room temperature, resulting in a fully homogeneous glass structure with robust mechanical properties. Furthermore, the self-passivating solid electrolyte interphase at the Na|SE interface is critical for interface stabilization and reversible Na plating and stripping. The new structural and compositional design strategies presented here provide a new paradigm in the development of safe, low-cost, energy-dense, and long-lifetime ASSSBs.
Exploring nonprecious metal electrocatalysts to replace the noble metal-based catalysts for full water electrocatalysis is still an ongoing challenge. In this work, porous structured ternary nickel-iron-phosphide (Ni-Fe-P) nanocubes were synthesized through one-step phosphidation of a Ni-Fe-based Prussian blue analogue. The Ni-Fe-P nanocubes exhibit a rough and loose porous structure on their surface under suitable phosphating temperature, which is favorable for the mass transfer and oxygen diffusion during the electrocatalysis process. As a result, Ni-Fe-P obtained at 350 °C with poorer crystallinity offers more unsaturated atoms as active sites to expedite the absorption of reactants. Additionally, the introduction of nickel improved the electronic structure and then reduced the charge-transfer resistance, which would result in a faster electron transport and an enhancement of the intrinsic electrocatalytic activities. Benefiting from the unique porous nanocubes and the chemical composition, the Ni-Fe-P nanocubes exhibit excellent hydrogen evolution reaction and oxygen evolution reaction activities in alkaline medium, with low overpotentials of 182 and 271 mV for delivering a current density of 10 mA cm, respectively. Moreover, the Ni-Fe-P nanocubes show outstanding stability for sustained water splitting in the two-electrode alkaline electrolyzer. This work not only provides a facile approach for designing bifunctional electrocatalysts but also further extends the application of metal-organic frameworks in overall water splitting.
NH3 synthesis by the electrocatalytic N2 reduction reaction (NRR) under ambient conditions is an appealing alternative to the currently employed industrial method—the Haber–Bosch process—that requires high temperature and pressure. We report single Mo atoms anchored to nitrogen‐doped porous carbon as a cost‐effective catalyst for the NRR. Benefiting from the optimally high density of active sites and hierarchically porous carbon frameworks, this catalyst achieves a high NH3 yield rate (34.0±3.6 μgNH3 h−1 mgcat.−1) and a high Faradaic efficiency (14.6±1.6 %) in 0.1 m KOH at room temperature. These values are considerably higher compared to previously reported non‐precious‐metal electrocatalysts. Moreover, this catalyst displays no obvious current drop during a 50 000 s NRR, and high activity and durability are achieved in 0.1 m HCl. The findings provide a promising lead for the design of efficient and robust single‐atom non‐precious‐metal catalysts for the electrocatalytic NRR.
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