Large Energy Barrier Research Articles

Intersections of two stacking faults in zincblende GaN

The structure and energetics of an isolated {111} stacking fault and the interactions of two non-coplanar {111} stacking faults in zincblende GaN are investigated using an empirical potential of the Tersoff-Brenner type. For a single stacking fault, a metastable configuration is found only when the fault is created on the {111} plane in the glide set, which results in local transformation into a more stable wurtzite structure. This energetically favorable configuration is separated from the unfaulted crystal by a large energy barrier. Interactions between two stacking faults on non-coplanar {111} planes, where one fault corresponds to the metastable configuration created in the glide set and the second fault is created on a different {111} plane, lead to a reduction of the aforementioned energy barrier and an increase of the energy of the second metastable fault. The intersection of the two faults results in a significant reconstruction of atomic positions around the line common to both faults. Apart from the wurtzite stacking, the structure of this intersection shows a partial transformation into the rocksalt structure that is normally stable only at high pressures. The presence of this high-energy rocksalt structure is avoided if the second fault is non-planar. In this case, four different structures of the intersection exist. We demonstrate that one of these structures agrees well with TEM observations.

Biophysical Characterization of Epigallocatechin-3-Gallate Effect on the Cardiac Sodium Channel Nav1.5.

Epigallocatechin-3-Gallate (EGCG) has been extensively studied for its protective effect against cardiovascular disorders. This effect has been attributed to its action on multiple molecular pathways and transmembrane proteins, including the cardiac Nav1.5 channels, which are inhibited in a dose-dependent manner. However, the molecular mechanism underlying this effect remains to be unveiled. To this aim, we have characterized the EGCG effect on Nav1.5 using electrophysiology and molecular dynamics (MD) simulations. EGCG superfusion induced a dose-dependent inhibition of Nav1.5 expressed in tsA201 cells, negatively shifted the steady-state inactivation curve, slowed the inactivation kinetics, and delayed the recovery from fast inactivation. However, EGCG had no effect on the voltage-dependence of activation and showed little use-dependent block on Nav1.5. Finally, MD simulations suggested that EGCG does not preferentially stay in the center of the bilayer, but that it spontaneously relocates to the membrane headgroup region. Moreover, no sign of spontaneous crossing from one leaflet to the other was observed, indicating a relatively large free energy barrier associated with EGCG transport across the membrane. These results indicate that EGCG may exert its biophysical effect via access to its binding site through the cell membrane or via a bilayer-mediated mechanism.

Studying rare events using forward-flux sampling: Recent breakthroughs and future outlook.

Rare events are processes that occur upon the emergence of unlikely fluctuations. Unlike what their name suggests, rare events are fairly ubiquitous in nature, as the occurrence of many structural transformations in biology and material sciences is predicated upon crossing large free energy barriers. Probing the kinetics and uncovering the molecular mechanisms of possible barrier crossings in a system is critical to predicting and controlling its structural and functional properties. Due to their activated nature, however, rare events are exceptionally difficult to study using conventional experimental and computational techniques. In recent decades, a wide variety of specialized computational techniques-known as advanced sampling techniques-have been developed to systematically capture improbable fluctuations relevant to rare events. In this perspective, we focus on a technique called forward flux sampling [Allen et al., J. Chem. Phys. 124, 024102 (2006)] and overview its recent methodological variants and extensions. We also provide a detailed overview of its application to study a wide variety of rare events and map out potential avenues for further explorations.

Characterizing the Translocation of Charged Peptide Loops across Lipid Bilayers with Molecular Dynamics Simulations

The hydrophobic core of the cell membrane is considered largely impermeable to charged molecules because of the large free energy barrier and corresponding long timescale (∼hours) for charge translocation. Contradicting this view, a variety of water-soluble peptides are known to translocate charged groups across the cell membrane on a surprisingly rapid timescale, on the order of few seconds at least for some peptides. In this work, we study the interconversion of a peptide with charged flanking loops between a surface-adsorbed and membrane-embedded state, which requires the translocation (or “flipping”) of charged loops across the bilayer. We utilize all-atom Temperature Accelerated Molecular Dynamics (TAMD) simulations to predict the likelihood of loop flipping without predefining a specific translocation pathway. We show that membrane-exposed charged residues accelerate the flipping of charged peptide loops by stabilizing intramembrane water defects. We further demonstrate that this computational approach can identify multiple flipping pathways without specifying them a priori. The position of charged residues in the transmembrane helix also affects the flipping pathways and the apparent flipping free energy barrier. These detailed molecular-level insights of peptide translocation pathways may be valuable for designing small cationic peptides for applications in gene and drug delivery. Moreover, the methodology and findings discussed here can generalize to more complex behaviors, such as the large-scale conformational rearrangements of integral membrane proteins.

Simulations of Ultralow-Power Nonvolatile Cells for Random-Access Memory

Dynamic random-access memory (DRAM), which represents 99% of random-access memory (RAM), is fast and has excellent endurance, but suffers from disadvantages such as short data-retention time (volatility) and loss of data during readout (destructive read). As a consequence, it requires persistent data refreshing, increasing energy consumption, degrading performance, and limiting scaling capacity. It is, therefore, desirable that the next generation of RAM will be nonvolatile RAM (NVRAM), have low power, have high endurance, be fast, and be nondestructively read. Here, we report on a new form of NVRAM: a compound-semiconductor charge-storage memory that exploits quantum phenomena for its operational advantages. Simulations show that the device consumes very little power, with 100 times lower switching energy per unit area than DRAM, but with similar operating speeds. Nonvolatility is achieved due to the extraordinary band offsets of InAs and AlSb, providing a large energy barrier (2.1 eV), which prevents the escape of electrons. Based on the simulation results, an NVRAM architecture is proposed for which extremely low disturb-rates are predicted as a result of the quantum-mechanical resonant-tunneling mechanism used to write and erase.

A Nonionic and Low-Entropic MA(MMA)nPbI3-Ink for Fast Crystallization of Perovskite Thin Films

Summary Conventional processing of the halide perovskite usually utilizes ionic precursor solutions containing mobile precursor ions in a high-boiling-point solvent. The assembly of these disordered ions into low-entropic crystals needs to overcome the large thermodynamic energy barrier. Traditional processes rely on high-temperature annealing and complex anti-solvent treatments to overcome this barrier, but they remain highly uncontrollable. Here, we report a novel nonionic and low-entropic MA(MMA)nPbI3 ink for fast perovskite crystallization with superior {110} preferred orientation and a high Lotgering factor. And the ink-based films exhibit an extraordinary long carrier diffusion length of 4.6 μm at the single-crystal level. With facial one-step processing, the corresponding photovoltaic cell exhibits a record efficiency of 21.8% based on the MAPbI3-system. Scaling of active area from 0.096 to 0.5 cm2 did not deteriorate the cell performance as the efficiency remained over 21%. These results demonstrate the potential of this nonionic ink for the industrial transition of perovskite photovoltaic technology.

Two-way tuning of structural order in metallic glasses

Metallic glasses are expected to have quite tunable structures in their configuration space, without the strict constraints of a well-defined crystalline symmetry and large energy barriers separating different states in crystals. However, effectively modulating the structure of metallic glasses is rather difficult. Here, using complementary in situ synchrotron x-ray techniques, we reveal thermal-driven structural ordering in a Ce65Al10Co25 metallic glass, and a reverse disordering process via a pressure-induced rejuvenation between two states with distinct structural order characteristics. Studies on other metallic glass samples with different compositions also show similar phenomena. Our findings demonstrate the feasibility of two-way structural tuning states in terms of their dramatic ordering and disordering far beyond the nearest-neighbor shells with the combination of temperature and pressure, extending accessible states of metallic glasses to unexplored configuration spaces.

CuN3 doped graphene as an active electrocatalyst for oxygen reduction reaction in fuel cells: A DFT study

Based on first-principles DFT calculations, copper-nitrogen embedded graphene (CuN3-Gra) is introduced as an efficient electrocatalyst for oxygen reduction reaction (ORR) in fuel cells. The possible reaction mechanisms as well as the corresponding stationary points on potential energy surfaces are studied in acidic media. Our results indicate that dissociation of O2 over CuN3-Gra cannot occur at normal condition due to its large energy barrier. In contrast, the O2 hydrogenation into OOH, followed by the hydrogenation of OOH into O and H2O species is the most favorable pathway for the ORR process. The energy barrier for rate-determining step of this reaction is calculated to be 1.00 eV which is related to the formation of first H2O molecule. The free energy diagrams reveal that for OOH hydrogenation pathway, all of the elementary steps are exothermic at potentials 0.0–0.8 V.

Dy2@C79N: a new member of dimetalloazafullerenes with strong single molecular magnetism.

Enhancing the exchange interaction between magnetic ions is a long-term target in molecular magnetism. Endohedral metallofullerenes (EMFs) provide a possibility for achieving such a goal by imprisoning multiple magnetic centers inside the confined inner space of a fullerene cage. Here, we report a new member of dimetallic azafullerene Dy2@C79N via crystallographic determination for the first time. Magnetic studies indicate that the strong ferromagnetic coupling between lanthanide ions and unpaired electrons enables Dy2@C79N to be a favorable SMM with large energy barrier of U = 669 K and observable hysteresis loops below 24 K.

Controllable growth of GeSi nanowires on trench patterned Si(001) substrate

Controllable growth of nanowires is a prerequisite for addressability and scalability of nanowire quantum devices. By combining top-down nanofabrication and bottom-up self-assembly, site-controlled GeSi nanowires with two (105) facets can be grown on Si (001) substrate with pre-patterned trenches. Trenches along the [100] or [010] crystallographic direction with 60 nm in width and 6 nm in height are fabricated on Si substrate by electron beam lithography and reactive ion etching. Subsequently, a 60-nm-thick Si buffer layer is grown at 330–400 ℃ on the patterned substrate to improve the surface quality. The facets at the tip of the trenches transform into (11n) after depositing the Si buffer layer. Self-organized GeSi nanowires form inside the trenches by depositing the 6-nm-thick Si<sub>67</sub>Ge<sub>33</sub> film at 450 ℃ followed by 1 h annealing at 510 ℃. The GeSi nanowires are (105)-faceted with an average height of approximately 7 nm. Furthermore, we systematically study the influence of annealing temperature, Ge concentration and pattern period on the formation of site-controllable GeSi nanowire on a patterned Si (001) substrate. The GeSi nanowires can be formed only inside the trenches within a specific annealing temperature ranging from 500 ℃ to 520 ℃. It is also discovered that GeSi nanowires are very sensitive to Ge concentration, as they cannot form at lower Ge concentration due to a large nucleation energy barrier. In contrast, high Ge concentration will lead to the discontinuity of nanowires caused by higher atomic diffusion barrier. The generated GeSi nanowires in the trenches exhibit similar dimensions at different pattern periods, which indicates that the growth process is thermodynamically determined. Overall, we realize the controllable growth of the GeSi nanowires, while the length of nanowires can reach the millimeter even centimeter scales, replying on the patterned trench length. The above results offer a controllable growth method of the Ge nanowires, which could potentially lead to the scalability of the Ge quantum devices on Si substrates.

Anomaly in the stability of the hydroxides of icosagens (B and Al) and their noble gas (Xe and Rn) derivatives: a comparative study.

Motivated by the discovery of neutral noble gas hydrides, herein, we have explored the possibility of the existence of a novel class of neutral noble gas compounds, HNgBO, HNgOB, HNgAlO and HNgOAl (Ng = Xe and Rn), through the insertion of a Ng atom into the hydroxides of icosagens and their isomers, namely, HBO, HOB, HAlO and HOAl. Second-order Møller-Plesset perturbation theory (MP2), density functional theory (DFT), and coupled-cluster theory (CCSD(T))-based methods have been employed to investigate the structures, stabilities, energetics, harmonic vibrational frequencies, and charge distribution of the predicted molecules. The HXeBO, HXeOAl, HRnBO, HRnAlO and HRnOAl molecules are found to be thermodynamically stable with respect to all plausible 2-body and 3-body dissociation channels except the 2-body dissociation pathway, leading to the formation of global minimum products (Ng + HBO), (Ng + HOAl) and (Ng + HAlO). However, the very large activation energy barrier heights provide enough kinetic stability to the predicted metastable molecules, which in turn can prevent them from dissociating into the global minimum products. Between the HNgBO-HNgOB isomers, HNgBO is found to be more stable, where both HNgBO and the precursor molecule HBO are linear. On the other hand, HNgOAl is more stable between the HNgAlO-HNgOAl isomers, where the precursor molecule HOAl is bent and HNgOAl is linear in contradiction and in agreement with Walsh's rule, respectively. Moreover, in contrast to the more stable HNgBO case, where the Ng atom is bonded with the icosagen atom, in the more stable HNgOAl, the Ng atom is connected to the chalcogen atom. All the detailed aforementioned analyses concerning the predicted molecules clearly indicate that a strong covalent bond exists between the H and Ng atoms, while an ionic interaction is found between the Ng and B atoms in HNgBO and Ng and O atoms in the HNgOAl molecules. In addition, the charge distribution and atoms-in-molecules (AIM) analyses are in agreement with the above-mentioned conclusion and also suggest that the predicted metastable HNgBO and HNgOAl molecules should essentially exist in the form of [HNg]+[BO]- and [HNg]+[OAl]-, respectively. All the calculated results reported in this work indicate that it might be possible to prepare and characterize the predicted molecules via suitable experimental technique(s) under cryogenic conditions.

Two LnIII4 (LnIII = Gd and Dy) clusters constructed by 8-hydroxyquinoline schiff base and β-diketonate coligand: Magnetic refrigeration property and single-molecule magnet behavior

Reaction between Ln(acac)3·2H2O (LnIII = Gd and Dy) and an 8-hydroxyquinoline Schiff base (HL) via solvothermal conditions yielded two new LnIII4 clusters [Ln4(acac)4(μ3-OH)2L6]·2CH3CN (HL = 5-(9-anthranylene)-8-hydroxylquinoline, Hacac = acetylacetone). In this paper, the structures and magnetic properties of the two LnIII4 clusters have been systematically characterized and studied. Structural studies indicate that both clusters 1 and 2 crystallize in the monoclinic space group P21/c. The four LnIII4 ions form a rhombus-shaped arrangement. Physical characterization reveals that cluster 1 displays the property of magnetic refrigeration with −ΔSm of 14.57 J kg−1 K−1 (ΔH = 7 T and T = 3.0 K), while cluster 2 shows single-molecule magnet (SMM) behavior with a large effective energy barrier (ΔE/kB) of 73.6 K.

Polyfluorene Copolymers as High‐Performance Hole‐Transport Materials for Inverted Perovskite Solar Cells

Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention due to their cost‐effective production. Hole‐transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. Herein, three polyfluorene copolymers (TFB, PFB, and PFO) are investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Due to its high mobility along with the favored energy‐level alignment with perovskite, TFB shows superior charge extraction and suppressed interfacial recombination than PFB‐ and PFO‐based devices, which delivers a high efficiency of 18.48% with an open‐circuit voltage (VOC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO‐based devices results in substantial losses in both VOC and photocurrent. These results demonstrate that TFB can serve as a superior HTM for inverted PSCs. Moreover, it is anticipated that the performance of the three HTMs identified here might guide the molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.

Highly active oxygen evolution integrated with efficient CO2 to CO electroreduction

Electrochemical reduction of CO2 to useful chemicals has been actively pursued for closing the carbon cycle and preventing further deterioration of the environment/climate. Since CO2 reduction reaction (CO2RR) at a cathode is always paired with the oxygen evolution reaction (OER) at an anode, the overall efficiency of electrical energy to chemical fuel conversion must consider the large energy barrier and sluggish kinetics of OER, especially in widely used electrolytes, such as the pH-neutral CO2-saturated 0.5 M KHCO3 OER in such electrolytes mostly relies on noble metal (Ir- and Ru-based) electrocatalysts in the anode. Here, we discover that by anodizing a metallic Ni-Fe composite foam under a harsh condition (in a low-concentration 0.1 M KHCO3 solution at 85 °C under a high-current ∼250 mA/cm2), OER on the NiFe foam is accompanied by anodic etching, and the surface layer evolves into a nickel-iron hydroxide carbonate (NiFe-HC) material composed of porous, poorly crystalline flakes of flower-like NiFe layer-double hydroxide (LDH) intercalated with carbonate anions. The resulting NiFe-HC electrode in CO2-saturated 0.5 M KHCO3 exhibited OER activity superior to IrO2, with an overpotential of 450 and 590 mV to reach 10 and 250 mA/cm2, respectively, and high stability for >120 h without decay. We paired NiFe-HC with a CO2RR catalyst of cobalt phthalocyanine/carbon nanotube (CoPc/CNT) in a CO2 electrolyzer, achieving selective cathodic conversion of CO2 to CO with >97% Faradaic efficiency and simultaneous anodic water oxidation to O2 The device showed a low cell voltage of 2.13 V and high electricity-to-chemical fuel efficiency of 59% at a current density of 10 mA/cm2.

Retraction of "Magnetic Hysteresis of Single-Molecule Magnets Adsorbed on Ferromagnetic Substrate".

Single-molecule magnets (SMMs), exhibiting magnetic bistability and a large energy barrier to the magnetization relaxation, are attractive candidates for realizing efficient spintronic devices such as ultra-high-density memories and quantum computers. Here, we demonstrate robust spin-polarization of a quintessential SMM, the double-decker bis(phthalocyaninato)terbium(III) (TbPc2) molecules, adsorbed on the bilayer Co islands on Au(111) using spin-polarized scanning tunneling microscopy, visualizing the switching of the SMM spin with submolecular resolution. Our results reveal that molecular spins of TbPc2 are antiferromagnetically coupled to the magnetization of the Co island, irrespective of the bonding configuration of the molecule. Stable spin-polarization is inferred from the substantial hysteresis observed in the magnetization curves measured over the molecules. This is in contrast to the reports of near-zero remanence for the bulk TbPc2 crystals and the TbPc2 molecules on a nonmagnetic substrate. The observation of a significant hysteretic opening can be attributed to the large magnetic anisotropy barrier of the molecule and the suppression of the quantum tunneling process. We anticipate that our approach of using the substrate to control and enhance the properties of a TbPc2 SMM will accelerate further research toward realization of SMM-based functional spintronic devices.

Enhancing Magnetic Hysteresis in Single-Molecule Magnets by Ligand Functionalisation

The design criteria for single-molecule magnets (SMMs) of dysprosium(III) to show large thermal energy barriers to magnetic reversal have been established and proven, and the challenge to enhance their performance is understanding and control of vibrational modes that govern slow relaxation. We have prepared a new SMM, [Dy(L)2(py)5][BPh4] 1 (where HL = (S)-(-)-1-phenylethanol), which is based on the archetype [Dy(OtBu)2(py)5][BPh4] 2. Compounds 1 and 2 have similarly large energy barriers of Ueff = 1130(20) cm-1 and Ueff = 1250(10) cm-1, and yet 1 shows magnetic hysteresis at a far higher temperature of 22 K (cf. TH = 4 K for 2). Ab initio calculation of the spin dynamics show that substitution of the alkoxide ligand in fact enhances relaxation over the energy barrier for 1 over 2, in agreement with experiment, and that the higher temperature of magnetic hysteresis owes to reduced quantum tunnelling at low temperatures.

Complexation Kinetics of Cyclodextrins with Bile Salt Anions: Energy Barriers for the Threading of Ionic Groups.

Binding constants for thousands of cyclodextrin complexes have been reported in the literature, but much less is known about the kinetics of these host-guest complexes. In the present study, inclusion complexes of bile salts with β-cyclodextrin, γ-cyclodextrin, and a methylated β-cyclodextrin were studied by nuclear magnetic resonance (NMR) lineshape analysis to explore the structural factors that govern the complexation kinetics. For complexes with β-cyclodextrin, the association rate constants ranged from 2 × 106 to 2 × 107 M-1 s-1 while the dissociation rate constants ranged from 12 to 6000 s-1 at 25 °C. The kinetics were thus significantly slower than for any other β-cyclodextrin complex reported in the literature, due to the large energy barrier for threading the ionic sidechains of the bile salt anions. Bile salts with taurine and glycine sidechains had identical binding affinities, but the kinetics differed by a factor of 10. Introduction of a single hydroxyl group at the binding site of the bile salts reduced the lifetimes and binding constants of the complexes by more than 50 times. The strong temperature dependence of the rate constants revealed that the large activation energies were mainly enthalpic with a small contribution from entropy. The larger γ-cyclodextrin was threaded by the nonionic end of the bile salts, and the kinetics were too fast to be accurately determined. The study demonstrates that ionic groups on guest molecules constitute significant energy barriers for the threading and dethreading of β-cyclodextrin hosts.

Polyol Solvation Effect on Tuning the Universal Growth of Binary Metal Oxide Nanodots@Graphene Oxide Heterostructures for Electrochemical Applications.

Tuning the uniformity and size of binary metal oxide nanodots on graphene oxide (BMO NDs@GO) is significant but full of challenges in wet-chemistry, owing to the difficulties of controlling the complicated cation/anion co-adsorption, heterogeneous nucleation, and overgrowth processes. Herein, the aim is to tune these processes by understanding the functions of various alcohol solvents for NDs growth on GO. It is found that the polyol solvation effect is beneficial for obtaining highly uniform BMO NDs@GO. Polyol shell capped metal ions exhibit stronger hydrogen-bond interactions with the GO surface, leading to a uniform cation/anion co-adsorption and followed heterogeneous nucleation. The polyol-solvated ions with large diffusion energy barrier drastically limit the ion diffusion kinetics in liquids and at the solid/liquid interface, resulting in a slow and controllable growth. Moreover, the synthesis in polyol systems is highly controllable and universal, thus eleven BMO and polynary metal oxide NDs@GO are obtained by this method. The synthetic strategy provides improved prospects for the manufacture of inorganic NDs and their expanding electrochemical applications.

Mechanistic origin of high strength in refractory BCC high entropy alloys up to 1900K

The body centered cubic (BCC) high entropy alloys (HEAs) MoNbTaW and MoNbTaVW show exceptional strength retention up to 1900K. The mechanistic origin of the retained strength is unknown yet is crucial for finding the best alloys across the immense space of BCC HEA compositions. Experiments on Nb-Mo, Fe-Si and Ti-Zr-Nb alloys report decreased mobility of edge dislocations, motivating a theory of strengthening of edge dislocations in BCC alloys. The strength of BCC HEAs can be controlled by edge dislocations, especially at high temperatures, because the random field of solutes in these high-concentration alloys creates large energy barriers for thermally-activated edge glide. A parameter-free theory for this mechanism of edge motion in BCC alloys qualitatively and quantitatively captures the strength versus temperature for both MoNbTaW and MoNbTaVW alloys and other BCC HEAs. A reduced analytic version of the theory, embodying the edge-strengthening mechanism, then enables screening over > 600,000 compositions in the Mo-Nb-Ta-V-W family to identify promising new compositions with high retained strength and/or reduced mass density. Overall, the theory reveals an unexpected mechanism - edge dislocation motion in the random alloy - as responsible for high temperature strength in BCC alloys and paves the way for theory-guided design of new high-performance HEAs.

Multidimensional Integrated Chalcogenides Nanoarchitecture Achieves Highly Stable and Ultrafast Potassium-Ion Storage.

Potassium-ion batteries (KIBs) have come into the spotlight in large-scale energy storage systems because of cost-effective and abundant potassium resources. However, the poor rate performance and problematic cycle life of existing electrode materials are the main bottlenecks to future potential applications. Here, the first example of preparing 3D hierarchical nanoboxes multidimensionally assembled from interlayer-expanded nano-2D MoS2 @dot-like Co9 S8 embedded into a nitrogen and sulfur codoped porous carbon matrix (Co9 S8 /NSC@MoS2 @NSC) for greatly boosting the electrochemical properties of KIBs in terms of reversible capacity, rate capability, and cycling lifespan, is reported. Benefiting from the synergistic effects, Co9 S8 /NSC@MoS2 @NSC manifest a very high reversible capacity of 403 mAh g-1 at 100 mA g-1 after 100 cycles, an unprecedented rate capability of 141 mAh g-1 at 3000 mA g-1 over 800 cycles, and a negligible capacity decay of 0.02% cycle-1 , boosting promising applications in high-performance KIBs. Density functional theory calculations demonstrate that Co9 S8 /NSC@MoS2 @NSC nanoboxes have large adsorption energy and low diffusion barriers during K-ion storage reactions, implying fast K-ion diffusion capability. This work may enlighten the design and construction of advanced electrode materials combined with strong chemical bonding and integrated functional advantages for future large-scale stationary energy storage.