Elucidating the Structural Evolution of O3-type NaNiFeMnO: A Prototype Cathode for Na-Ion Battery.

Extending the depth-of-charge (DoC) of the layered oxide cathode presents an essential route to improve the competitiveness of the Na-ion battery versus the commercialized LiFePO-based Li-ion battery (0.8 CNY/Wh). However, the DoC-dependent boundary between detrimental/irreversible structural distortion and neutral/reversible structure interconversion cannot be clearly distinguished, which is attributed to the ambiguous recognition of correlation among the complex phase transition, local covalent environment evolution, and charge compensation.

Electrolyte Solvation Engineering Stabilizing Anode-Free Sodium Metal Battery With 4.0 V-Class Layered Oxide Cathode.

Anode-free sodium metal batteries (AFSMBs) are regarded as the "ceiling" for current sodium-based batteries. However, their practical application is hindered by the unstable electrolyte and interfacial chemistry at the high-voltage cathode and anode-free side, especially under extreme temperature conditions. Here, an advanced electrolyte design strategy based on electrolyte solvation engineering is presented, which shapes a weakly solvating anion-stabilized (WSAS) electrolyte by balancing the interaction between the Na-solvent and Na-anion.

Impurity-healing interface engineering for efficient perovskite submodules.

An issue that affects the scaling-up development of perovskite photovoltaics is the marked efficiency drop when enlarging the device area, caused by the inhomogeneous distribution of defected sites. In the narrow band gap formamidinium lead iodide (FAPbI), the native impurities of PbI and δ-FAPbI non-perovskite could induce unfavoured non-radiative recombination, as well as inferior charge transport and extraction. Here we develop an impurity-healing interface engineering strategy to address the issue in small-area solar cells and large-scale submodules.

Structural and Na-ion diffusion behavior of O3/P3/P2-type NaNi1/3Mn1/3Fe1/3O2 cathode for Na-ion batteries from first-principles study.

A layered sodium-ion battery cathode, O3/P3/P2-type NaNi1/3Mn1/3Fe1/3O2, has been systematically investigated by first-principles density functional theory to explore the detailed structural and Na-ion diffusion behavior during desodiation. Our results suggest that the (NaO6) spacing is greatest in the P3 phase and lowest in the O3 phase, with the P2 phase exhibiting intermediate spacing. During desodiation, the intermediate stages have a greater (NaO6) spacing than the initial and final stages.

TiB and SrB monolayers: high capacity and zero strain-like anode materials for Li/Na/K/Ca ion batteries.

Storage capacity, average open circuit voltage (OCV), diffusion barrier, lattice parameter changes, are key indicators of whether a material would be suitable for use as a Li-ion or non-Li-ion battery (LIB or NLIB) anode. The rapid development of 2D materials over the past few decades has opened up new possibilities for these metrics. Using first-principles calculations, we prove that two 2D materials, TiB and SrB, show excellent performance in terms of the above metrics when used as anodes for LIBs or NLIBs.

Theoretical prediction on net boroxene as a promising Li/Na-ion batteries anode.

Novel two-dimensional (2D) electrode materials have become a new frontier for mining electrode materials for Li-ion batteries (LIBs) and Na-ion batteries (NIBs). Herein, based on first-principles calculations, we present a systematic study on the Li and Na storage behaviors in Calypso-predicted completely flat 2D boron oxide (l-BO) with large mesh pores. We start our calculations from geometrical optimization, followed by a performance evaluation of Li/Na adsorption and migration processes.

Theoretical study on the magnetic properties of cathode materials in the lithium-ion battery.

The layered LiMO (M = Co, Ni, and Mn) materials are commonly used as the cathode materials in the lithium-ion battery due to the distinctive layer structure for lithium extraction and insertion. Although their electrochemical properties have been extensively studied, the structural and magnetic properties of LiNiO are still under considerable debate, and the magnetic properties of monoclinic LiMnO are seldom reported. In this work, a detailed study of LiNiO, LiMnO, and a half-doped material LiNiMnO is performed via both first-principles calculations and Monte Carlo simulations based on the effective spin Hamiltonian model.

Tuning a small electron polaron in FePO by P-site or O-site doping based on DFT+ and KMC simulation.

Due to the existence of a small polaron, the intrinsic electronic conductivity of olivine-structured LiFePO is quite low, limiting its performance as a cathode material for lithium-ion batteries (LIBs). Previous studies have mainly focused on improving intrinsic conductivity through Fe-site doping while P-site or O-site doping has rarely been reported. Herein, we studied the formation and dynamics of the small electron polaron in FePXO and FePOZ by employing the density functional theory with the on-site Hubbard correction terms (DFT+) and Kinetic Monte Carlo (KMC) simulation, where X and Z indicate the doping elements (X = S, Se, As, Si, V; Z = S, F, Cl), and and β indicate the light doping at the P position ( = 0.

Two-dimensional metal-phase layered molybdenum disulfide for electrocatalytic hydrogen evolution reaction.

The two-dimensional (2D) basal plane of metal-phase molybdenum disulphide (1T-MoS) provides a large area of active sites to significantly reduce the overpotential of the hydrogen evolution reaction (HER), but the long preparation period limits its industrial application. Here, 1T-MoS catalysts derived from molybdenum blue solution (MBS) were prepared in one step using a rapid high-pressure microwave (MW-MoS) strategy. This method eliminated the thermodynamic process with a long time required for Mo-O trioxide bond breakage and reduction (Mo → Mo) of the conventional hydrothermal method.

A Metal-Organic Frameworks Derived 1T-MoS with Expanded Layer Spacing for Enhanced Electrocatalytic Hydrogen Evolution.

Metal phase molybdenum disulfide (1T-MoS ) is considered a promising electrocatalyst for hydrogen evolution reaction (HER) due to its activated basal and superior electrical conductivity. Here, a one-step solvothermal route is developed to prepare 1T-MoS with expanded layer spacing through the derivatization of a Mo-based organic framework (Mo-MOFs). Benefiting from N,N-dimethylformamide oxide as external stress, the interplanar spacing of (002) of the MoS catalyst is extended to 10.

The Mechanism of Li Deposition on the Cu Substrates in the Anode-Free Li Metal Batteries.

Due to the rapid growth in the demand for high-energy-density Lithium (Li) batteries and insufficient global Li reserves, the anode-free Li metal batteries are receiving increasing attention. Various strategies, such as surface modification and structural design of copper (Cu) current collectors, have been proposed to stabilize the anode-free Li metal batteries. Unfortunately, the mechanism of Li deposition on the Cu surfaces with the different Miller indices is poorly understood, especially on the atomic scale.

Self-Healing Mechanism of Lithium in Lithium Metal.

Li is an ideal anode material for use in state-of-the-art secondary batteries. However, Li-dendrite growth is a safety concern and results in low coulombic efficiency, which significantly restricts the commercial application of Li secondary batteries. Unfortunately, the Li-deposition (growth) mechanism is poorly understood on the atomic scale.

High Cycling Stability of the LiNi Co Mn O Cathode via Surface Modification with Polyimide/Multi-Walled Carbon Nanotubes Composite Coating.

The Ni-rich LiNi Co Mn O (NCM811) cathode coated by combining with multi-walled carbon nanotubes (MWCNTs) and polyimide (PI) produces a PI3-NCM811 cathode, which markedly improves cycling stability and suppresses secondary crystal cracking. The initial discharge capacity of the PI3-NCM811 cathode is 199.6 mAh g between 2.

Effects of Strain and Electric Field on Molecular Doping in MoSSe.

Recently, synthesized Janus MoSSe monolayers have attracted tremendous attention in science and technology due to their novel properties and promising applications. In this work, we investigate their molecular adsorption-induced structural and electronic properties and tunable doping effects under biaxial strain and external electric field by first-principles calculations. We find an effective n-type or p-type doping in the MoSSe monolayer caused by noncovalent tetrathiafulvalene (TTF) or tetracyanoquinodimethane (TCNQ) molecular adsorption.

The thermodynamics and electronic structure analysis of P-doped spinel CoO.

The thermodynamics of phosphorus (P) doping to spinel CoO, for both bulk cases and (100) and (110) surface cases, is studied using first principles calculations. The doping energies of the P atom at different doping sites are carefully calculated and compared. It is shown that P doping at Co sites, at either tetrahedral or octahedral sites, is energetically favorable, while P doping and replacing O atoms are energetically unfavorable.

Sequence-Defined Peptoids with -OH and -COOH Groups As Binders to Reduce Cracks of Si Nanoparticles of Lithium-Ion Batteries.

Silicone (Si) is one type of anode materials with intriguingly high theoretical capacity. However, the severe volume change associated with the repeated lithiation and delithiation processes hampers the mechanical/electrical integrity of Si anodes and hence reduces the battery's cycle-life. To address this issue, sequence-defined peptoids are designed and fabricated with two tailored functional groups, "-OH" and "-COOH", as cross-linkable polymeric binders for Si anodes of LIBs.

Hydrogen solution in tungsten (W) under different temperatures and strains: a first principles calculation study.

In this paper, H solution behaviors are systematically studied under varied external tensile/compressive strains in bcc W using first-principles calculations. The results show that the H solution energy is not only dependent on the ground state energy of the W lattice, but also strongly dependent on the entropy effect. The entropy effect includes not only the contribution from lattice vibrations, but also the configurational entropy of the H distribution in the interstitial sites.

Efficient potential-tuning strategy through p-type doping for designing cathodes with ultrahigh energy density.

Designing new cathodes with high capacity and moderate potential is the key to breaking the energy density ceiling imposed by current intercalation chemistry on rechargeable batteries. The carbonaceous materials provide high capacities but their low potentials limit their application to anodes. Here, we show that Fermi level tuning by p-type doping can be an effective way of dramatically raising electrode potential.

Surface Modification of the LiNiCoMnO Cathode Material by Coating with FePO with a Yolk-Shell Structure for Improved Electrochemical Performance.

Coating with FePO with the size of 20-30 nm on the surface of a LiNiCoMnO (NCM811) cathode produces an LFP3@NCM811 cathode via a sol-gel method, which markedly reduces secondary crystal cracking. A stable particle structure greatly improves the cycling stability of the LFP3@NCM811cathode, which retains 97% of its initial discharge capacity compared to NCM811 (78%) after 100 cycles at 2.7-4.

Improving the Interfacial Stability between Lithium and Solid-State Electrolyte via Dipole-Structured Lithium Layer Deposited on Graphene Oxide.

Utilization of lithium (Li) metal anode in solid-state batteries (SSBs) with sulfide solid-state electrolyte (SSE) is hindered by the instable Li/SSE interface. A general solution to solve this problem is to place an expensive indium (In) foil between the SSE and Li, while it decreases the output voltage and thus the energy density of the battery. In this work, an alternative strategy is demonstrated to boost the cycling performances of SSB by wrapping a graphene oxide (GO) layer on the anode.

Dissociation of (LiO) on graphene and boron-doped graphene: insights from first-principles calculations.

Reducing charge overpotential is of great significance to enhance the efficiency and cyclability of Li-O batteries. Here, a dramatically reduced charge overpotential via boron-doped graphene as a catalytic substrate is successfully predicted. By first-principles calculations, from the perspective of reaction thermodynamics and kinetics, the results show that the electrochemical oxidation of the LiO cation is easier than the chemical oxidation of the neutral LiO molecule, and the oxidation of (LiO) is facilitated by boron-doping in pristine graphene.

First-principles study of χ-borophene for charge-modulated switchable CO capture.

A first-principles calculation was performed to investigate the switchable CO2 capture on χ3-borophene by injecting/removing the extra electrons. The results show that the CO2 adsorption energy on the neutral χ3-borophene is 0.150 eV.