The reasonable design of electrode materials for rechargeable batteries plays an important role in promoting the development of renewable energy technology. With the in‐depth understanding of the mechanisms underlying electrode reactions and the rapid development of advanced technology, the performance of batteries has significantly been optimized through the introduction of defect engineering on electrode materials. A large number of coordination unsaturated sites can be exposed by defect construction in electrode materials, which play a crucial role in electrochemical reactions. Herein, recent advances regarding defect engineering in electrode materials for rechargeable batteries are systematically summarized, with a special focus on the application of metal‐ion batteries, lithium–sulfur batteries, and metal–air batteries. The defects can not only effectively promote ion diffusion and charge transfer but also provide more storage/adsorption/active sites for guest ions and intermediate species, thus improving the performance of batteries. Moreover, the existing challenges and future development prospects are forecast, and the electrode materials are further optimized through defect engineering to promote the development of the battery industry.

Manipulating a quantum state via electrostatic gating has been of great importance for many model systems in nanoelectronics. Until now, however, controlling the electron spins or, more specifically, the magnetism of a system by electric-field tuning has proven challenging. Recently, atomically thin magnetic semiconductors have attracted significant attention due to their emerging new physical phenomena. However, many issues are yet to be resolved to convincingly demonstrate gate-controllable magnetism in these two-dimensional materials. Here, we show that, via electrostatic gating, a strong field effect can be observed in devices based on few-layered ferromagnetic semiconducting CrGeTe. At different gate doping, micro-area Kerr measurements in the studied devices demonstrate bipolar tunable magnetization loops below the Curie temperature, which is tentatively attributed to the moment rebalance in the spin-polarized band structure. Our findings of electric-field-controlled magnetism in van der Waals magnets show possibilities for potential applications in new-generation magnetic memory storage, sensors and spintronics.

Demand for energy in day to day life is increasing exponentially. However, existing energy storage technologies like lithium ion batteries cannot stand alone to fulfill future needs. In this regard, potassium ion batteries (KIBs) that utilize K ions in their charge storage mechanism have attracted considerable attention due to their unique properties and are therefore established as one of the future battery systems of interest among the scientific community. Nevertheless, the development and identification of appropriate electrode materials is very essential for practical applications. This review features the current development in KIBs electrode and electrolyte materials, the present challenges facing this technology (in the commercial aspect), and future aspects to develop fully functional KIBs. The potassium storage mechanisms, evolution of the KIBs, and the advantages and disadvantages of each category of materials are included. Additionally, various approaches to enhance the electrochemical performances of KIBs are also discussed. This review is not only an amalgamation of different viewpoints in literature, but also contains concise perspectives and strategies. Moreover, the potential emergence of a novel class of K‐based dual ion batteries is also analyzed for the first time.

Iron phthalocyanine (FePc) is a promising non-precious catalyst for the oxygen reduction reaction (ORR). Unfortunately, FePc with plane-symmetric FeN 4 site usually exhibits an unsatisfactory ORR activity due to its poor O 2 adsorption and activation. Here, we report an axial Fe-O coordination induced electronic localization strategy to improve its O 2 adsorption, activation and thus the ORR performance. Theoretical calculations indicate that the Fe-O coordination evokes the electronic localization among the axial direction of O-FeN 4 sites to enhance O 2 adsorption and activation. To realize this speculation, FePc is coordinated with an oxidized carbon. Synchrotron X-ray absorption and Mössbauer spectra validate Fe-O coordination between FePc and carbon. The obtained catalyst exhibits fast kinetics for O 2 adsorption and activation with an ultralow Tafel slope of 27.5 mV dec −1 and a remarkable half-wave potential of 0.90 V. This work offers a new strategy to regulate catalytic sites for better performance.

An all redox flow lithium battery with strikingly high energy density is successfully demonstrated.

Water contamination is generally considered to be detrimental to the performance of aprotic lithium-air batteries, whereas this view is challenged by recent contrasting observations. This has provoked a range of discussions on the role of water and its impact on batteries. In this work, a distinct battery chemistry that prevails in water-contaminated aprotic lithium-oxygen batteries is revealed. Both lithium ions and protons are found to be involved in the oxygen reduction and evolution reactions, and lithium hydroperoxide and lithium hydroxide are identified as predominant discharge products. The crystallographic and spectroscopic characteristics of lithium hydroperoxide monohydrate are scrutinized both experimentally and theoretically. Intriguingly, the reaction of lithium hydroperoxide with triiodide exhibits a faster kinetics, which enables a considerably lower overpotential during the charging process. The battery chemistry unveiled in this mechanistic study could provide important insights into the understanding of nominally aprotic lithium-oxygen batteries and help to tackle the critical issues confronted.

The redox-targeting reactions can disruptively boost the energy density but introduce additional free-energy loss. Here, the Nernstian-potential-driven redoxtargeting reaction considerably eliminates the voltage loss of the system while maintaining a high energy density. Driven by the Nernstian potential difference, the redox molecule, a ferrocene-grafted ionic liquid with standard potential identical to that of LiFePO 4 , reacts with the solid material both anodically and cathodically and exhibits near-unity solid material utilization, 95% voltage efficiency, and energy density.

Electrochemical CO 2 reduction is a promising way to mitigate CO 2 emissions and close the anthropogenic carbon cycle. Among products from CO 2 RR, multicarbon chemicals, such as ethylene and ethanol with high energy density, are more valuable. However, the selectivity and reaction rate of C 2 production are unsatisfactory due to the sluggish thermodynamics and kinetics of C−C coupling. The electric field and thermal field have been studied and utilized to promote catalytic reactions, as they can regulate the thermodynamic and kinetic barriers of reactions. Either raising the potential or heating the electrolyte can enhance C−C coupling, but these come at the cost of increasing side reactions, such as the hydrogen evolution reaction. Here, we present a generic strategy to enhance the local electric field and temperature simultaneously and dramatically improve the electric−thermal synergy desired in electrocatalysis. A conformal coating of ∼5 nm of polytetrafluoroethylene significantly improves the catalytic ability of copper nanoneedles (∼7-fold electric field and ∼40 K temperature enhancement at the tips compared with bare copper nanoneedles experimentally), resulting in an improved C 2 Faradaic efficiency of over 86% at a partial current density of more than 250 mA cm −2 and a record-high C 2 turnover frequency of 11.5 ± 0.3 s −1 Cu site −1 . Combined with its low cost and scalability, the electric−thermal strategy for a state-of-the-art catalyst not only offers new insight into improving activity and selectivity of value-added C 2 products as we demonstrated but also inspires advances in efficiency and/or selectivity of other valuable electro-/photocatalysis such as hydrogen evolution, nitrogen reduction, and hydrogen peroxide electrosynthesis.