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.

The dependence of differential capacity versus voltage (dQ/dV) of Li/NCA half cells on temperature and testing current (C-rate) was studied. Kinetic hindrance of lithium diffusion at both low (∼3.5 V vs Li/Li + ) and high states of charge (∼4.17 V) was observed. In-situ X-ray diffraction measured the volume changes of the NCA lattice versus state of charge. NCA/graphite pouch cells were cycled in various voltage ranges to explore the impacts of depth of discharge (DOD) ranges and the kinetic hindrance regions in NCA on cell failure. dV/dQ analysis, full cell impedance and symmetric cell impedance analysis as well as half-cell studies of recovered electrodes were performed after 0, ∼400 and 800 charge-discharge cycles. The contributions of active mass loss and shift loss (from loss of Li inventory) to the capacity fade of NCA/graphite cells under various testing conditions were determined. The increase in positive electrode charge transfer impedance with cycle number was proportional to the increase of positive electrode active mass loss. There was no strong correlation between positive electrode active mass loss and lattice volume change. NCA active mass loss during cycling can be minimized when the dQ/dV peaks at ∼3.5 and 4.17 V (vs. Li/Li + ), that show kinetic hindrance, are partially or completely avoided.

Rational design and bottom-up synthesis based on the structural topology is a promising way to obtain two-dimensional metal–organic frameworks (2D MOFs) in well-defined geometric morphology. Herein, a topology-guided bottom-up synthesis of a novel hexagonal 2D MOF nanoplate is realized. The hexagonal channels constructed via the distorted (3,4)-connected Ni2(BDC)2(DABCO) (BDC = 1,4-benzene­dicarboxylic acid, DABCO = 1,4-diazabicyclo[2.2.2]­octane) framework serve as the template for the specifically designed morphology. Under the inhibition and modulation of pyridine through a substitution–suppression process, the morphology can be modified from hexagonal nanorods to nanodisks and to nanoplates with controllable thickness tuned by the dosage of pyridine. Subsequent pyrolysis treatment converts the nanoplates into a N-doped Ni@carbon electrocatalyst, which exhibits a small overpotential as low as 307 mV at a current density of 10 mA cm–2 in the oxygen evolution reaction.

Silicon (Si) has been attracting extensive attention for rechargeable lithium (Li)‐ion batteries due to its high theoretical capacity and low potential vs Li/Li+. However, it remains challenging and problematic to stabilize the Si materials during electrochemical cycling because of the huge volume expansion, which results in losing electric contact and pulverization of Si particles. Consequently, the Si anode materials generally suffer from poor cycling, poor rate performance, and low coulomb efficiency, preventing them from practical applications. Up‐to‐date, there are numerous reports on the engineering of Si anode materials at microscale and nanoscale with significantly improved electrochemical performances. In this review, we will concentrate on various precisely designed protective layers for silicon‐based materials, including carbon layers, inorganic layers, and conductive polymer protective layer. First, we briefly introduced the alloying and failure mechanism of Si as anode materials upon electrochemical reactions. Following that, representative cases have been introduced and summarized to illustrate the purpose and advancement of protective coating layers, for instance, to alleviate pulverization and improve conductivity caused by volume expansion of Si particles during charge/discharge process, and maintain the surface stability of Si particles to form a stable solid‐electrolyte interphase layer. At last, possible strategies on the protective coating layer for stabilizing silicon anode materials that can be applied in the future have been indicated.

The BDF (Beijing Density Functional) program package is in the first place a platform for theoretical and methodological developments, standing out particularly in relativistic quantum chemical methods for chemistry and physics of atoms, molecules, and periodic solids containing heavy elements. These include the whole spectrum of relativistic Hamiltonians and their combinations with density functional theory for the electronic structure of ground states as well as time-dependent and static density functional linear response theories for electronically excited states and electric/magnetic properties. However, not to be confused by its name, BDF nowadays comprises also of standard and novel wave function-based correlation methods for the ground and excited states of strongly correlated systems of electrons [e.g., multireference configuration interaction, static–dynamic–static configuration interaction, static–dynamic–static second-order perturbation theory, n-electron valence second-order perturbation theory, iterative configuration interaction (iCI), iCI with selection plus PT2, and equation-of-motion coupled-cluster]. Additional features of BDF include a maximum occupation method for finding excited states of Hartree–Fock/Kohn–Sham (HF/KS) equations, a very efficient localization of HF/KS and complete active space self-consistent field orbitals, and a unique solver for exterior and interior roots of large matrix eigenvalue problems.

The handling of positive electrode active materials must be done carefully due to their propensity to degrade when exposed to ambient atmosphere. The growth of impurities on Ni-rich layered lithium transition metal oxides (LTMOs) is particularly concerning as these materials readily react with H2O and CO2 in atmosphere. The resulting surface impurity species have detrimental effects on the performance of the Li-ion cell and are commonly removed by washing the positive electrode active materials. However, little is understood about the reaction between these materials and aqueous solutions. In this study, LTMOs samples were exposed to acidic and neutral aqueous solutions for various periods of time. The resulting material samples were analysed by X-ray powder diffraction (XRD), thermogravimetric analysis coupled with mass spectrometry (TGA-MS), and by scanning electron microscopy (SEM). The solutions collected after washing were analysed by pH titration and inductively coupled plasma optical emission spectrometry (ICP-OES). From this, we propose two pH-dependent regimes that define the reaction between the positive electrode material and the aqueous solution used for washing. Possible consequences of these reactions on cell performance and lifetime are discussed.

Graphene membranes with subnanopores are considered to be the next-generation materials for water desalination and ion separation, while their performance is mainly determined by the relative ion selectivity of the pores. However, the origin of this phenomenon has been controversial in the past few years, which strongly limits the development of related applications. Here, using direct Au ion bombardment, we fabricated the desired subnanopores with average diameters of 0.8 ± 0.16 nm in monolayer graphene. The pores showed the ability to sieve K+, Na+, Li+, Cs+, Mg2+, and Ca2+ cations, and the observed K+/Mg2+ selectivity ratio was over 4. With further molecular dynamics simulations, we demonstrated that the ion selectivity is primarily attributed to the dehydration process of ions that can be quantitatively described by the ion-dependent free-energy barriers. Hopefully, this work is helpful in further enhancing the ion selectivity of graphene nanopores and also presenting a new paradigm for improving the performance of other nanoporous atomically thin membranes, such as MXenes and MoS2.

Layered serpentine Ni3Ge2O5(OH)4 is compositionally active and structurally favorable for adsorption and diffusion of reactants in oxygen evolution reactions (OER). However, one of the major problems for these materials is limited active sites and low efficiency for OER. In this regard, a new catalyst consisting of layered serpentine Ni3Ge2O5(OH)4 nanosheets is introduced via a controlled one‐step synthetic process where the morphology, size, and layers are well tailored. The theoretical calculations indicate that decreased layers and increased exposure of (100) facets in serpentine Ni3Ge2O5(OH)4 lead to much lower Gibbs free energy in adsorption of reactive intermediates. Experimentally, it is found that the reduction in number of layers with minimized particle size exhibits plenty of highly surface‐active sites of (100) facets and demonstrates a much enhanced performance in OER than the corresponding multilayered nanosheets. Such a strategy of tailoring active sites of serpentine Ni3Ge2O5(OH)4 nanosheets offers an effective method to design highly efficient electrocatalysts.