Energy level regulation of anions via hydrogen bond effects to construct a stable solid electrolyte interface for a high-stability lithium metal anode.

An intermolecular hydrogen bond between 2,5-dihydroxyterephthalic acid and the anions in the Li+ solvation shell is constructed to promote the formation of a LiF-rich SEI on a metallic Li electrode. Li metal batteries with improved cyclability (140 cycles under an N/P ratio of 4.9) and high capacity retention (90%) are eventually obtained.

Controllable Regulation of the Oxygen Redox Process in Lithium-Oxygen Batteries by High-Configuration-Entropy Spinel with an Asymmetric Octahedral Structure.

Designing bifunctional electrocatalysts to boost oxygen redox reactions is critical for high-performance lithium-oxygen batteries (LOBs). In this work, high-entropy spinel (Co0.2Mn0.2Ni0.2Fe0.2Cr0.2)3O4 (HEOS) is fabricated by modulating the internal configuration entropy of spinel and studied as the oxygen electrode catalyst in LOBs. Under the high-entropy atomic environment, the Co-O octahedron in spinel undergoes asymmetric deformation, and the reconfiguration of the electron structure around the Co sites leads to the upward shift of the d-orbital centers of the Co sites toward the Fermi level, which is conducive to the strong adsorption of redox intermediate LiO2 on the surface of the HEOS, ultimately forming a layer of a highly dispersed Li2O2 thin film. Thin-film Li2O2 is beneficial for ion diffusion and electron transfer at the electrode-electrolyte interface, which makes the product easy to decompose during the charge process, ultimately accelerating the kinetics of oxygen redox reactions in LOBs. Based on the above advantages, HEOS-based LOBs deliver high discharge/charge capacity (12.61/11.72 mAh cm-2) and excellent cyclability (424 cycles). This work broadens the way for the design of cathode catalysts to improve oxygen redox kinetics in LOBs.

Optimized Lithium Ion Coordination via Chlorine Substitution to Enhance Ionic Conductivity of Garnet-Based Solid Electrolytes.

Garnet-type solid-state electrolytes attract abundant attentions due to the broad electrochemical window and remarkable thermal stability while their poor ionic conductivity obstructs their widespread application in all-solid-state batteries. Herein, the enhanced ionic conductivity of garnet-type solid electrolytes is achieved by partially substituting O2- sites with Cl- anions, which effectively reduce Li+ migration barriers while preserving the highly conductive cubic phase of garnet-type solid-state electrolytes. This substitution not only weakens the anchoring effect of anions on Li+ to widen the size of Li+ diffusion channel but also optimizes the occupancy of Li+ at different sites, resulting in a substantial reduction of the Li+ migration barrier and a notable improvement in ionic conductivity. Leveraging these advantageous properties, the developed Li6.35 La3 Zr1.4 Ta0.6 O11.85 -Cl0.15 (LLZTO-0.15Cl) electrolyte demonstrates high Li+ conductivity of 4.21×10-6  S cm-1 . When integrated with LiFePO4 (LFP) cathode and metallic lithium anode, the LLZTO-0.15Cl electrolyte enables the solid-state battery to operate for more than 100 cycles with a high capacity retention of 76.61% and superior Coulombic efficiency of 99.48%. This work shows a new strategy for modulating anionic framework to enhance the conductivity of garnet-type solid-state electrolytes.

Structure and Charge Regulation Strategy Enabling Superior Cycling Stability of Ni-Rich Cathode Materials.

Ni-rich layered oxides LiNixCoyMn1-x-yO2 (NCMs, x > 0.8) are the most promising cathode candidates for Li-ion batteries because of their superior specific capacity and cost affordability. Unfortunately, NCMs suffer from a series of formidable challenges such as structural instability and incompatibility with commonly used electrolytes, which seriously hamper their practical applications on a large scale. Herein, the Al/Ta codoping modification strategy is proposed to improve the performance of the LiNi0.83Co0.1Mn0.07O2 cathode, and the as-prepared Al/Ta-modified LiNi0.83Co0.1Mn0.07O2 delivers exceptional cycling stability with a capacity retention of 97.4% after 150 cycles at 1C and an excellent rate performance with a high capacity of 143.2 mAh g-1 even at 3C. Based on the experimental study, it is found that the structural stability of NCM is strengthened due to the regulated coordination of oxygen by introducing a robust Ta-O covalent bond, which prevents the layered structure from collapsing. Moreover, the reconstructed rock-salt-like surface is capable of effectively inhibiting interfacial side reactions as well as the overgrowth of the cathode-electrolyte interface. Theoretically, the energy of Li/Ni mixing is significantly increased with the introduction of Al and Ta elements in Al/Ta codoped NCM, leading to inhibited adverse phase transition during cycling. A feasible pathway for designing and developing advanced Ni-rich cathode materials for Li-ion batteries is provided in this work.

Adjusting Li+ Solvation Structures via Dipole-Dipole Interaction to Construct Inorganic-Rich Interphase for High-Performance Li Metal Batteries.

Practical applications of lithium metal batteries are limited by unstable solid electrolyte interphase (SEI) and uncontrollable dendrite Li deposition. Regulating the solvation structure of Li+ via modifying electrolyte components enables optimizing the structure of the SEI and realizing dendrite-free Li deposition. In this work, it is found that the ionic-dipole interactions between the electron-deficient B atoms in lithium oxalyldifluoro borate (LiDFOB) and the O atoms in the DME solvent molecule can weaken the interaction between the DME molecule and Li+, accelerating the desolvation of Li+. On this basis, the ionic-dipole interactions facilitate the entry of abundant anions into the inner solvation sheath of Li+, which promotes the formation of inorganic-rich SEI. In addition, the interaction between DFOB- and DME molecules reduces the highest occupied molecular orbital energy level of DME molecules in electrolytes, which improves the oxidative stability of the electrolytes system. As a result, the Li||Li cells in LiDFOB-containing electrolytes exhibit an excellent cyclability of over 1800 h with a low overpotential of 18.2 mV, and the Li||LiFePO4 full cells display a high-capacity retention of 93.4% after 100 cycles with a high Coulombic efficiency of 99.3%.

Prediction of a planar BxP monolayer with inherent metallicity and its potential as an anode material for Na and K-ion batteries: a first-principles study.

Borophene, the lightest two-dimensional material, exhibits exceptional storage capacity as an anode material for sodium-ion batteries (NIBs) and potassium-ion batteries (PIBs). However, the pronounced surface activity gives rise to strong interfacial bonding between borophene and the metal substrate it grows on. Incorporation of heterogeneous atoms capable of forming strong bonds with boron to increase borophene stability while preserving its intrinsic metallic conductivity and high theoretical capacity remains a great challenge. In this study, a particle swarm optimization (PSO) method was employed to determine several new two-dimensional monolayer boron phosphides (BxP, x = 3-6) with rich boron components. The obtained BxP has great potential to be used as an anode material for sodium-ion batteries/potassium-ion batteries (SIBs/PIBs), according to DFT calculations. BxP demonstrates remarkable stability compared with borophene which ensures their feasibility of experimental synthesis. Moreover, B5P and B6P exhibit high electronic conductivity and ionic conductivity, with migration energy barriers of 0.20 and 0.21 eV for Na ions and 0.07 eV for K ions. Moreover, the average open circuit voltage falls within a favorable range of 0.25-0.73 V, which results in a high storage capacity of 1119-2103 mA h g-1 for SIBs and 631-839 mA h g-1 for PIBs. This study paves the way for exploring boron-rich 2D electrode materials for energy applications and provides valuable insights into the functionalization and stabilization of borophene.

Adjusting the 3d Orbital Occupation of Ti in Ti3 C2 MXene via Nitrogen Doping to Boost Oxygen Electrode Reactions in Li-O2 Battery.

Rationally designing efficient catalysts is the key to promote the kinetics of oxygen electrode reactions in lithium-oxygen (Li-O2 ) battery. Herein, nitrogen-doped Ti3 C2 MXene prepared via hydrothermal method (N-Ti3 C2 (H)) is studied as the efficient Li-O2 battery catalyst. The nitrogen doping increases the disorder degree of N-Ti3 C2 (H) and provides abundant active sites, which is conducive to the uniform formation and decomposition of discharge product Li2 O2 . Besides, density functional theory calculations confirm that the introduction of nitrogen can effectively modulate the 3d orbital occupation of Ti in N-Ti3 C2 (H), promote the electron exchange between Ti 3d orbital and O 2p orbital, and accelerate oxygen electrode reactions. Specifically, the N-Ti3 C2 (H) based Li-O2 battery delivers large discharge capacity (11 679.8 mAh g-1 ) and extended stability (372 cycles). This work provides a valuable strategy for regulating 3d orbital occupancy of transition metal in MXene to improve the catalytic activity of oxygen electrode reactions in Li-O2 battery.

Surface-Preferred Crystal Plane Growth Enabled by Underpotential Deposited Monolayer toward Dendrite-Free Zinc Anode.

Aqueous Zn batteries with ideal energy density and absolute safety are deemed the most promising candidates for next-generation energy storage systems. Nevertheless, stubborn dendrite formation and notorious parasitic reactions on the Zn metal anode have significantly compromised the Coulombic efficiency (CE) and cycling stability, severely impeding the Zn metal batteries from being deployed in the proposed applications. Herein, instead of random growth of Zn dendrites, a guided preferential growth of planar Zn layers is accomplished via atomic-scale matching of the surface lattice between the hexagonal close-packed (hcp) Zn(002) and face-centered cubic (fcc) Cu(100) crystal planes, as well as underpotential deposition (UPD)-enabled zincophilicity. The underlying mechanism of uniform Zn plating/stripping on the Cu(100) surface is demonstrated by ab initio molecular dynamics simulations and density functional theory calculations. The results show that each Zn atom layer is driven to grow along the exposed closest packed plane (002) in hcp Zn metal with a low lattice mismatch with Cu(100), leading to compact and planar Zn deposition. In situ optical visualization inspection is adopted to monitor the dynamic morphology evolution of such planar Zn layers. With this surface texture, the Zn anode exhibits exceptional reversibility with an ultrahigh Coulombic efficiency (CE) of 99.9%. The MnO2//Zn@Cu(100) full battery delivers long cycling stability over 548 cycles and outstanding specific energy and power density (112.5 Wh kg-1 even at 9897.1 W kg-1). This work is expected to address the issues associated with Zn metal anodes and promote the development of high-energy rechargeable Zn metal batteries.

Interfacial Electron Redistribution of Hydrangea-like NiO@Ni2 P Heterogeneous Microspheres with Dual-Phase Synergy for High-Performance Lithium-Oxygen Battery.

Lithium-oxygen batteries (LOBs) with ultra-high theoretical energy density (≈3500 Wh kg-1 ) are considered as the most promising energy storage systems. However, the sluggish kinetics during the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) can induce large voltage hysteresis, inferior roundtrip efficiency and unsatisfactory cyclic stability. Herein, hydrangea-like NiO@Ni2 P heterogeneous microspheres are elaborately designed as high-efficiency oxygen electrodes for LOBs. Benefitting from the interfacial electron redistribution on NiO@Ni2 P heterostructure, the electronic structure can be modulated to ameliorate the chemisorption of the intermediates, which is confirmed by density functional theory (DFT) calculations and experimental characterizations. In addition, the interpenetration of the PO bond at the NiO@Ni2 P heterointerface leads to the internal doping effect, thereby boosting electron transfer to further improve ORR and OER activities. As a result, the NiO@Ni2 P electrode shows a low overpotential of only 0.69 V, high specific capacity of 18254.1 mA h g-1 and superior long-term cycling stability of over 1400 h. The exploration of novel bifunctional electrocatalyst in this work provides a new solution for the practical application of LOBs.

A multifunctional protective layer with biomimetic ionic channel suppressing dendrite and side reactions on zinc metal anodes.

A multifunctional graphitic carbon nitride (GCN) protective layer with bionic ion channels and high stability is prepared to inhibit dendrite growth and side reactions on zinc (Zn) metal anodes. The high electronegativity of the nitrogen-containing organic groups (NOGs) in the GCN layer can effectively promote the dissociation of solvated Zn2+ and its rapid transportation in bionic ion channels via a hopping mechanism. In addition, this GCN layer exhibits excellent mechanical strength to suppress the growth of Zn dendrites and the volume expansion of Zn metal anodes during the plating process. Consequently, the electrodeposited Zn presents a uniform and densely packed morphology with negligible side-product accumulation. As a result, the half-cell composed of the Cu-GCN anode can deliver a remarkable long-term cycling performance of 1000 h at 0.5 mA cm-2 and 0.25 mAh cm-2. A full cell assembled with MnO2 cathode also displays improved long-term cycling performance (150 cycles at 200 mA g-1) when the Cu-GCN@Zn composite anode is applied. This work deepens our understanding of the kinetics of ion migration in the interface layer and paves the way for next-generation high energy-density Zn-metal batteries (ZMBs).

Synergy of cobalt vacancies and iron doping in cobalt selenide to promote oxygen electrode reactions in lithium-oxygen batteries.

Electronic structural engineering plays a key role in the design of high-efficiency catalysts. Here, to achieve optimal electronic states, introduction of exotic Fe dopant and Co vacancy into CoSe2 nanosheet (denoted as Fe-CoSe2-VCo) is presented. The obtained Fe-CoSe2-VCo demonstrates excellent catalytic activity as compared to CoSe2. Experimental results and density functional theory (DFT) calculations confirm that Fe dopant and Co defects cause significant electron delocalization, which reduces the adsorption energy of LiO2 intermediate on the catalyst surface, thereby obviously improving the electrocatalytic activity of Fe-CoSe2-VCo towards oxygen redox reactions. Moreover, the synergistic effect between Co vacancy and Fe dopant is able to optimize the microscopic electronic structure of Co ion, further reducing the energy barrier of oxygen electrode reactions on Fe-CoSe2-VCo. And the lithium-oxygen batteries (LOBs) based on Fe-CoSe2-VCo electrodes demonstrate a high Coulombic efficiency (CE) of about 72.66%, a large discharge capacity of about 13723 mA h g-1, and an excellent cycling life of about 1338 h. In general, the electronic structure modulation strategy with the reasonable introduction of vacancy and dopant is expected to inspire the design of highly efficient catalysts for various electrochemical systems.

Adjusting the d-band center of metallic sites in NiFe-based Bimetal-organic frameworks via tensile strain to achieve High-performance oxygen electrode catalysts for Lithium-oxygen batteries.

Developing effective electrocatalyst and fundamentally understanding the corresponding working mechanism are both urgently desired to overcome the current challenges facing lithium-oxygen batteries (LOBs). Herein, a series of NiFe-based bimetal-organic frameworks (NiFe-MOFs) with certain internal tensile strain are fabricated via a simple organic linker scission strategy, and served as cathode catalysts for LOBs. The introduced tensile strain broadens the inherent interatomic distances, leading to an upshifted d-band center of metallic sites and thus the enhancement of the adsorption strength of catalysts surface towards intermediates, which is contributed to rationally regulate the crystallinity of discharge product Li2O2. As a result, the uniformly distributed amorphous film-like Li2O2 tightly deposits on the surface of strain-regulated MOF, resulting in excellent electrochemical performance of LOBs, including a large discharge capacity of 12317.4 mAh g-1 at 100 mA g-1 and extended long-term cyclability of 357 cycles. This work presents a novel insight in adjusting the adsorption strength of cathode catalysts towards intermediates via introducing tensile strain in catalysts, which is a pragmatic strategy for improving the performance of LOBs.

Boosted Li+ transference number enabled via interfacial engineering for dendrite-free lithium metal anodes.

Adverse dendritic growth destabilizes Li metal anodes (LMAs), dramatically limiting the commercial applications of Li metal batteries (LMBs). Herein, ZIF-67 with unsaturated coordinative metal sites is used to construct a protective coating to immobilize anions, which is capable of increasing the Li+ transference number (tLi+) to mitigate the electrolyte concentration gradient in the vicinity of LMAs. In addition, the ZIF-67-based layer provides highly ordered ionic diffusion pathways, thus enabling dendrite-free Li deposition. With a considerable Li+ transference number of 0.57, ZIF-67-Cu@Li symmetric cells deliver a superior long-term performance (over 1000 h), and Li-O2 full batteries with ZIF-67-Cu@Li electrodes display a high energy density of 1911.61 W h kg-1.

Rationalizing Surface Electronic Configuration of Ni-Fe LDO by Introducing Cationic Nickel Vacancies as Highly Efficient Electrocatalysts for Lithium-Oxygen Batteries.

Cationic defect engineering is an effective strategy to optimize the electronic structure of active sites and boost the oxygen electrode reactions in lithium-oxygen batteries (LOBs). Herein, Ni-Fe layered double oxides enriched with cationic nickel vacancies (Ni-Fe LDO-VNi ) are first designed and studied as the electrocatalysts for LOBs. Based on the density functional theory calculation, the existence of nickel vacancy in Ni-Fe LDO-VNi significantly improves its intrinsic affinity toward intermediates, thereby fundamentally optimizing the formation and decomposition pathway of Li2 O2 . In addition, the number of eg electrons on each nickel site is 1.19 for Ni-Fe LDO-VNi , which is much closer to 1 than 1.49 for Ni-Fe LDO. The near-unity occupation of eg orbital enhances the covalency of transition metal-oxygen bonds and thus improves the electrocatalytic activity of Ni-Fe LDO-VNi toward oxygen electrode reactions. The experimental results show that the LOBs with Ni-Fe LDO-VNi electrode deliver low overpotentials of 0.11/0.29 V during the oxygen reduction reaction/oxygen evolution reaction, respectively, large specific capacities of 13 933 mA h g-1 and superior cycling stability of over 826 h. This study provides a novel approach to optimize the electrocatalytic activity of LDO through reasonable defect engineering.

Synergistic Effect of Microstructure Engineering and Local Crystal Structure Tuning to Improve the Cycling Stability of Ni-Rich Cathodes.

Ultrahigh Ni-rich layered oxides have been regarded as one of the most promising cathode candidates. However, cycling instability induced by interfacial reactions and irreversible H2-H3 lattice distortion is yet to be demonstrated by an effective strategy that could construct a stable grain interface and microstructure. Here, Ni-rich cathode LiNi0.92Co0.05Mn0.03O2 is modified by B and Ti to realize the synchronous regulation of a microstructure and the oxygen framework robustness. Compared with the large equiaxed crystalline grains for the pristine cathode, highly elongated grains with a strong radially oriented crystallographic texture in which the (003) facet is maximized are produced for Ti and B-modified LiNi0.92Co0.05Mn0.03O2. With the suppressed H2-H3 phase transition and cation mixing provided by radially oriented grains and turned local crystal oxygen framework robustness during cycling, the co-modified cathode exhibits enhanced Li+ diffusion kinetics and a capacity retention of 78.3% after 100 cycles, which outperformed the 38.5% for the pristine cathode. The improved cycling performance suggests the significance of the turned microstructure and local crystal structure in suppressing internal strain and crystal structure degradation. The synchronous realization of microstructure engineering and local crystal structure turning by optimal element combination would provide a heuristic solution for the construction of high perform Ni-rich cathodes.

Two-Dimensional Boron-Rich Monolayer BxN as High Capacity for Lithium-Ion Batteries: A First-Principles Study.

Owing to lightweight, abundant reserves, low cost, and nontoxicity, B-based two-dimensional (2D) materials, e.g., borophene, exhibit great potential as new anode materials with higher energy density for Li-ion batteries (LIBs). However, exfoliation of borophene from the Ag substrate remains the most daunting challenge due to their strong interfacial interactions, significantly restricting its practical applications. In this study, through first-principles swarm-intelligence structure calculations, we have found several Boron-rich boron nitride BxN materials (x = 2, 3, 4, and 5) with increased stability and weakened interactions with the Ag(111) substrate compared with δ6-borophene. A high cohesive energy and superior dynamical, thermodynamic, and mechanical stability provide strong feasibility for their experimental synthesis. The obtained BxN materials exhibit a high mechanical strength (94-226 N/m) and low interfacial bonding with the Ag substrate, from -0.043 to -0.054 eV Å-2, significantly smaller than that of δ6-borophene. Among them, B3N and B5N exhibit not only a remarkably high storage capacity of 1805-3153 mAh/g but also a low barrier energy and open-circuit voltage. Moreover, B2N showed a cross-sheet motion with a low barrier of 0.24 eV, which is unique compared with the in-plane diffusion in most other 2D electrode materials restricted by their quasi-flat geometry. BxN also exhibits excellent cyclability with improved metallic conductivity upon Li-ion intercalation, showing great potential in LIB applications. This study opens up a new avenue to explore B-rich 2D electrode materials in energy applications and provide instructive insights into borophene functionalization and exfoliation.

Adjusting the Covalency of Metal-Oxygen Bonds in LaCoO3 by Sr and Fe Cation Codoping to Achieve Highly Efficient Electrocatalysts for Aprotic Lithium-Oxygen Batteries.

Developing high-efficiency dual-functional catalysts to promote oxygen electrode reactions is critical for achieving high-performance aprotic lithium-oxygen (Li-O2) batteries. Herein, Sr and Fe cation-codoped LaCoO3 perovskite (La0.8Sr0.2Co0.8Fe0.2O3-σ, LSCFO) porous nanoparticles are fabricated as promising electrocatalysts for Li-O2 cells. The results demonstrate that the LSCFO-based Li-O2 batteries exhibit an extremely low overpotential of 0.32 V, ultrahigh specific capacity of 26 833 mA h g-1, and superior long-term cycling stability (200 cycles at 300 mA g-1). These prominent performances can be partially attributed to the existence of abundant coordination unsaturated sites caused by oxygen vacancies in LSCFO. Most importantly, density functional theory (DFT) calculations reveal that codoping of Sr and Fe cations in LaCoO3 results in the increased covalency of Co 3d-O 2p bonds and the transition of Co3+ from an ordinary low-spin state to an intermediate-spin state, eventually resulting in the transformation from nonconductor LCO to metallic LSCFO. In addition, based on the theoretical calculations, it is found that the inherent adsorption capability of LSCFO toward the LiO2 intermediate is reduced due to the increased covalency of Co 3d-O 2p bonds, leading to the formation of large granule-like Li2O2, which can be effectively decomposed on the LSCFO surface during the charging process. Notably, this work demonstrates a unique insight into the design of advanced perovskite oxide catalysts via adjusting the covalency of transition-metal-oxygen bonds for high-performance metal-air batteries.

Surface atomic modulation of CoP bifunctional catalyst for high performance Li-O2 battery enabled by high-index (211) facets.

The rational design of the surface structure and morphology characteristics of the catalyst at atomic level are the key to improve the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in lithium-oxygen (Li-O2) battery. Here a series of cobalt phosphide (CoP) electrocatalysts with a variety of index facets are successfully prepared including concave polyhedrons CoP exposing with (211) crystal planes (CoP CPHs) spherical nanoparticles CoP exposed with (011) crystal planes and polyhedron particles CoP exposing with (011) and (111) crystal planes. The results show that CoP CPHs based Li-O2 battery presents a large discharge capacity of 33743 mA h g-1 at current density of 50 mA g-1 and a remarkable long cycle life of up to 950 h. The experimental results demonstrates that the CoP CPHs electrode exposing with high-index (211) facets based Li-O2 battery exhibits an extremely low overpotential (0.67 V) ultrahigh specific capacity (33743 mAh g-1) and remarkable long-term stability of up to 950 h. Most importantly density functional theory (DFT) calculations demonstrate the excellent electrocatalytic activity of high-index (211) facets as compared to the low-index (011) and (111) planes are because of the existence of large density of atomic steps edge ledge sites and kinks which supply a wide space for breaking chemical bonds and increasing the reaction activity for oxygen electrode.

Rationalizing the Effect of Oxygen Vacancy on Oxygen Electrocatalysis in Li-O2 Battery.

Albeit the effectiveness of surface oxygen vacancy in improving oxygen redox reactions in Li-O2 battery, the underpinning reason behind this improvement remains ambiguous. Herein, the concentration of oxygen vacancy in spinel NiCo2 O4 is first regulated via magnetron sputtering and its relationship with catalytic activity is comprehensively studied in Li-O2 battery based on experiment and density functional theory (DFT) calculation. The positive effect posed by oxygen vacancy originates from the up shifted antibond orbital relative to Fermi level (Ef ), which provides extra electronic state around Ef , eventually enhancing oxygen adsorption and charge transfer during oxygen redox reactions. However, with excessive oxygen vacancy, the negative effect emerges because the metal ions are mostly reduced to low valence based on the electrical neutral principle, which not only destabilizes the crystal structure but also weakens the ability to capture electrons from the antibond orbit of Li2 O2 , leading to poor catalytic activity for oxygen evolution reaction (OER).

A 3D free-standing Co doped Ni2P nanowire oxygen electrode for stable and long-life lithium-oxygen batteries.

Exploring oxygen electrodes with superior bifunctional catalytic activity and suitable architecture is an effective strategy to improve the performance of lithium-oxygen (Li-O2) batteries. Herein, the internal electronic structure of Ni2P is regulated by heteroatom Co doping to improve its catalytic activity for oxygen redox reactions. Meanwhile, magnetron sputtering N-doped carbon cloth (N-CC) is used as a scaffold to enhance the electrical conductivity. The deliberately designed Co-Ni2P on N-CC (Co-Ni2P@N-CC) with a typical 3D interconnected architecture facilitates the formation of abundant solid-liquid-gas three-phase reaction interfaces inside the architecture. Furthermore, the rational catalyst/substrate interfacial interaction is capable of inducing a solvation-mediated pathway to form toroidal-Li2O2. The results show that the Co-Ni2P@N-CC based Li-O2 battery exhibits an ultra-low overpotential (0.73 V), enhanced rate performance (4487 mA h g-1 at 500 mA g-1) and durability (stable operation over 671 h). The pouch-type battery based on the Co-Ni2P@N-CC flexible electrode runs stably for 581 min in air without obvious voltage attenuation. This work verifies that heterogeneous atom doping and interface interaction can remarkably strengthen the performance of Li-O2 cells and thus pave new avenues towards developing high-performance metal-air batteries.