One of the greatest challenges for our society is providing powerful electrochemical energy conversion and storage devices. Rechargeable lithium‐ion batteries and fuel cells are amongst the most promising candidates in terms of energy densities and power densities. Nanostructured materials are currently of interest for such devices because of their high surface area, novel size effects, significantly enhanced kinetics, and so on. This Progress Report describes some recent developments in nanostructured anode and cathode materials for lithium‐ion batteries, addressing the benefits of nanometer‐size effects, the disadvantages of ‘nano’, and strategies to solve these issues such as nano/micro hierarchical structures and surface coatings, as well as developments in the discovery of nanostructured Pt‐based electrocatalysts for direct methanol fuel cells (DMFCs). Approaches to lowering the cost of Pt catalysts include the use of i) novel nanostructures of Pt, ii)new cost‐effective synthesis routes, iii) binary or multiple catalysts, and iv) new catalyst supports. magnified image

As low-cost electrocatalysts for oxygen reduction reaction applied to fuel cells and metal-air batteries, atomic-dispersed transition metal-nitrogen-carbon materials are emerging, but the genuine mechanism thereof is still arguable. Herein, by rational design and synthesis of dual-metal atomically dispersed Fe,Mn/N-C catalyst as model object, we unravel that the O₂ reduction preferentially takes place on Fe^III in the FeN₄ /C system with intermediate spin state which possesses one e_g electron (t_2g4e_g1) readily penetrating the antibonding π-orbital of oxygen. Both magnetic measurements and theoretical calculation reveal that the adjacent atomically dispersed Mn-N moieties can effectively activate the Fe^III sites by both spin-state transition and electronic modulation, rendering the excellent ORR performances of Fe,Mn/N-C in both alkaline and acidic media (halfwave positionals are 0.928 V in 0.1 M KOH, and 0.804 V in 0.1 M HClO₄), and good durability, which outperforms and has almost the same activity of commercial Pt/C, respectively. In addition, it presents a superior power density of 160.8 mW cm⁻² and long-term durability in reversible zinc–air batteries. The work brings new insight into the oxygen reduction reaction process on the metal-nitrogen-carbon active sites, undoubtedly leading the exploration towards high effective low-cost non-precious catalysts.