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Hollow LiFePO 4 nanoparticles were synthesized via a solvothermal technique, using ammonium tartrate as additive and carbon source, and ethylene glycol/water as solvent. The as-prepared samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning and transmission electron microscopies, and Brunauer–Emmett–Teller specific surface area measurements. The electrochemical properties of the LiFePO 4 cathode were examined in coin-type cell configuration and the cathode exhibited excellent rate capability (i.e., discharge capacity of 120.9 mA h g −1 at 10 C) and cycling performance (i.e., >98% of capacity retention rate after 50 cycles). It is believed that the enhanced performance is correlated to the hollow structure, small crystallite and particle sizes, and relatively shorter lattice parameter b . [ABSTRACT FROM AUTHOR]

Structure-property relations are central to understanding functional materials, and for battery research the use of neutron powder diffraction to reveal the atomistic and molecular-scale origin of battery performance characteristics is often essential. Although operando experiments of this kind are increasingly common as neutron sources and instrumentation advance, these experiments are hindered by the often large barrier presented by the preparation of whole batteries that yield a neutron diffraction signal from the electrode of interest that is sufficient to extract detailed structural information. This article presents a custom battery that is specifically designed for operando neutron powder diffraction. The battery is a pouch type and contains layers of positive and negative electrodes in a parallel-connecting stack. Importantly, the battery can be easily prepared in most laboratories, is configurable, and can be used with both lithium and sodium charge carriers. This paper provides some example operando neutron powder diffraction studies using this battery. [ABSTRACT FROM AUTHOR]

We used in situ neutron powder diffraction(NPD) to study the migrationof Li in Li4Ti5O12anodes with differentparticle sizes during battery cycling. The motivation of this workwas to uncover the mechanism of the increased capacity of the batterymade with a smaller-particle-sized anode. In real time, we monitoredthe anode lattice parameter, Li distribution, and oxidation stateof the Ti atom, and these suggested an increase in the rate of Liincorporation into the anode rather than a change in the migrationpathway as a result of the particle size reduction. The lattice ofthese anodes during continuous lithiation undergoes expansion followedby a gradual contraction and then expansion again. The measured latticeparameter changes were reconciled with Li occupation at specific siteswithin the Li4Ti5O12crystal structure,where Li migrates from the 8ato 16csites. Despite these similar Li-diffusion pathways, in larger-particle-sizedLi4Ti5O12the population of Li atthe 16csite is accompanied by Li depopulation fromthe 8asite, which is in contrast to the smaller-particle-sizedanode where our results suggest that Li at the 8asite is replenished faster than the rate of transfer of Li to the16csite. Fourier-difference nuclear density mapsof both anodes suggest that 32esites are involvedin the diffusion pathway of Li. NPD is again shown to be an excellenttool for the study of electrode materials for Li-ion batteries, particularlywhen it is used to probe real-time crystallographic changes of thematerials in an operating battery during charge–discharge cycling. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the application of neutron powder diffraction on studying the time-resolved structural evolution of a cell comprised with LiNi0.5Mn1.5O4 cathode and Li4Ti5O12 anode during charge–discharge cycling is demonstrated. As expected, the lattices of the LiNi0.5Mn1.5O4 cathode and the Li4Ti5O12 anode in the cell are found to simultaneously contract during charging and expand during discharging. It is found that for the LiNi0.5Mn1.5O4 cathode a solid-solution reaction is associated with the lattice change and the Ni2+/Ni3+ redox couple between 3.06 and 3.16 V (vs. Li4Ti5O12), and a two-phase reaction between Li x Ni0.5Mn1.5O4 and Ni0.25Mn0.75O2 is corresponding to the Ni3+/Ni4+ redox couple at voltage higher than 3.22 V (vs. Li4Ti5O12) without a corresponding change in lattice. The oxidation states of the metals in the electrodes are determined by tracking the associated change in the oxygen position. In addition, the Ti oxidation state is correlated to the intensity of the Li4Ti5O12 222 reflection at the anode, and the determined oxidation state of the Ni is correlated to the lithium occupancy within the cathode. Furthermore, the small volume changes of the cathode and the anode upon cycling suggest that the cell chemistry is favorable for practical applications. [Copyright &y& Elsevier]

Mg-substituted LiNi0.5−x Mg x Mn1.5O4 (x = 0, 0.02, 0.05, and 0.10) are prepared via a spray pyrolysis method followed by a two-step heating at 600 °C for 6 h and 800 °C for 8 h in air. The compositions, morphology, and crystalline structure are studied with ICP-OES, SEM, XRD, and NPD, respectively. The XRD and NPD results are refined with Rietveld method to reveal the crystallography and phase composition of the prepared samples. The electrochemical properties of the obtained samples are investigated with results of capacity retention and cyclic voltammetric studies. Samples synthesized in this study manifest promising rate capability that may be due to the presence of major phase with a minor amount of P4332. Among the prepared samples, LiNi0.4Mg0.1Mn1.5O4 demonstrates the lowest capacity fading rate among the prepared samples at 0.1 ∼ 5C rates when cycled between 3.5 and 5.1 V at temperatures of 30 and 60 °C. [ABSTRACT FROM AUTHOR]

In this work, 2D ferromagnetic M3GeTe2 (MGT, M = Ni/Fe) nanosheets with rich atomic Te vacancies (2D‐MGTv) are demonstrated as efficient OER electrocatalyst via a general mechanical exfoliation strategy. X‐ray absorption spectra (XAS) and scanning transmission electron microscope (STEM) results validate the dominant presence of metal‐O moieties and rich Te vacancies, respectively. The formed Te vacancies are active for the adsorption of OH* and O* species while the metal‐O moieties promote the O* and OOH* adsorption, contributing synergistically to the faster oxygen evolution kinetics. Consequently, 2D‐Ni3GeTe2v exhibits superior OER activity with only 370 mV overpotential to reach the current density of 100 mA cm−2 and turnover frequency (TOF) value of 101.6 s−1 at the overpotential of 200 mV in alkaline media. Furthermore, a 2D‐Ni3GeTe2v‐based anion‐exchange membrane (AEM) water electrolysis cell (1 cm2) delivers a current density of 1.02 and 1.32 A cm−2 at the voltage of 3 V feeding with 0.1 and 1 m KOH solution, respectively. The demonstrated metal‐O coordination with abundant atomic vacancies for ferromagnetic M3GeTe2 and the easily extended preparation strategy would enlighten the rational design and fabrication of other ferromagnetic materials for wider electrocatalytic applications. [ABSTRACT FROM AUTHOR]

Manganese‐based layered oxides are currently of significant interest as cathode materials for sodium‐ion batteries due to their low toxicity and high specific capacity. However, the practical applications are impeded by sluggish intrinsic Na+ migration and poor structure stability as a result of Jahn–Teller distortion and complicated phase transition. In this study, a high‐entropy strategy is proposed to enhance the high‐voltage capacity and cycling stability. The designed P2‐Na0.67Mn0.6Cu0.08Ni0.09Fe0.18Ti0.05O2 achieves a deeply desodiation and delivers charging capacity of 158.1 mAh g−1 corresponding to 0.61 Na with a high initial Coulombic efficiency of 98.2 %. The charge compensation is attributed to the cationic and anionic redox reactions conjunctively. Moreover, the crystal structure is effectively stabilized, leading to a slight variation of lattice parameters. This research carries implications for the expedited development of low‐cost, high‐energy‐density cathode materials for sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

Lattice‐oxygen redox in layered metal oxide cathodes offers a promising way to exploit high‐energy density sodium‐ion batteries. However, oxidation and reduction of lattice‐oxygen are always asymmetric, showing poor reversibility upon charging and discharging due to the activated oxygen loss and subsequent structural rearrangement. Here, a layered Na0.7[Li0.2Mn0.7Co0.1]O2 (NLMCO) is developed by balancing lattice‐oxygen activity and reversibility, which can deliver a record energy density of 729.7 Wh kg−1, further exceeding the state‐of‐the‐art Na0.75[Li0.25Mn0.75]O2 (NLMO, 638.4 Wh kg−1). In light of electron paramagnetic resonance spectroscopy, in situ differential electrochemical mass spectroscopy, and electrochemical testing results, the highly activated lattice‐oxygen is effectively stabilized in NLMCO without oxygen molecule release while obvious oxygen release is detected in the highly activated NLMO. Benefiting from the enhanced transition metal‐oxygen covalency and reduced band energy gap, the NLMCO electrode demonstrates simultaneously high lattice‐oxygen activity and reversibility, thus resulting in excellent rate and cycling performance, as well as ultra‐high energy density. The findings highlight the critical association of energy density and lattice‐oxygen redox reversibility, which will inspire more interest in anionic redox‐based high‐energy batteries. [ABSTRACT FROM AUTHOR]

The cycle life of aqueous zinc‐ion batteries (ZIBs) is limited by the notable challenges of cathode dissolution, water reactivity, and zinc dendrites. Here, it is demonstrated that by tuning the electrolyte solvation structure, the issues for both the electrodes and the electrolyte can be addressed simultaneously. Specifically, a fire‐retardant triethyl phosphate (TEP) is demonstrated as a cosolvent with strong solvating ability in a nonaqueous/aqueous hybrid electrolyte. The TEP features a higher donor number (26 kcal mol−1) than H2O (18 kcal mol−1), preferring to form a TEP occupied inner solvation sheath around Zn2+ and strong hydrogen bonding with H2O. The TEP coordinated electrolyte structure can inhibit the reactivity of H2O with V2O5 and leads to a robust polymeric‐inorganic interphase (poly‐ZnP2O6 and ZnF2) on zinc anode effectively preventing the dendrite growth and parasitic water reaction. With such an optimized electrolyte, the Zn/Cu cells perform high average Coulombic efficiency of 99.5%, and the full cell with a low capacity ratio of Zn:V2O5 (2:1) and lean electrolyte (11.5 g Ah−1) delivers a reversible capacity of 250 mAh g−1 for over 1000 cycles at 5 A g−1. This study highlights the promise of a successful electrolyte regulation strategy for the development of high‐performance and practical ZIBs. [ABSTRACT FROM AUTHOR]

LiCoO2 (LCO) with average particle distribution of 8 μm (LCO‐A) and 11 μm (LCO‐B) exhibit substantial differences in cycle performance. The half‐cells have similar first‐cycle discharge capacities of 173 and 175 mAh/g at 0.25 C, but after 100 cycles, the discharge capacities are substantially different, that is, 114 and 141 mAh/g for LCO‐A and LCO‐B, respectively. Operando neutron powder diffraction of full LCO||Li4Ti5O12 batteries show differences in the LCO reaction mechanism underpinning the electrochemical behavior. LCO‐A follows a purely solid solution reaction during cycling compared to the solid solution and two‐phase reaction mechanism in LCO‐B. The absence of the two‐phase reaction in LCO‐A is consistent with a homogeneous distribution of Li throughout the particle. The two‐phase reaction in LCO‐B reflects two distinguishable distributions of Li within the particles. The faster capacity decay in LCO‐A is correlated to an increase in electrode cracking during battery cycles. [ABSTRACT FROM AUTHOR]

The search for viable carbon‐neutral sources of renewable energy is one of the most critical challenges in science today. The chemical community is committed to seeking efficient, inexpensive, and sustainable electrocatalysts that can exploit the energy produced by sustainable energy resources. Here, an ethanol organocatalyst, which is green and cheap, that can efficiently catalyze the oxidation of Li2S in the electrochemical reactions of Li2S cathodes is identified. This study demonstrates that a multitude of small molecular organocatalysts will offer electrochemists an elegant tool for accelerating electrochemical reactions with otherwise unattainable efficiency and precision. This concept refashions electrochemical domains and has broad implications for the design of "green" and sustainable chemistry cycles. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been regarded as promising cathode materials for alkali‐ion batteries owing to their high theoretical energy density and low cost. However, the high water and vacancy content of PBAs lower their energy density and bring safety issues, impeding their large‐scale application. Herein, a facile "potassium‐ions assisted" strategy is proposed to synthesize highly crystallized PBAs. By manipulating the dominant crystal plane and suppressing vacancies, the as‐prepared PBAs exhibit increased redox potential resulting in high energy density up to ≈450 Wh kg−1, which is at the same level of the well‐known LiFePO4 cathodes for lithium‐ion batteries. Remarkably, unconventional highly‐reversible phase evolution and redox‐active pairs were identified by multiple in situ techniques for the first time. The preferred guest‐ion storage sites and migration mechanism were systematically analysed through theoretical calculations. We believe these results could inspire the design of safe with high energy density. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been regarded as promising cathode materials for alkali‐ion batteries owing to their high theoretical energy density and low cost. However, the high water and vacancy content of PBAs lower their energy density and bring safety issues, impeding their large‐scale application. Herein, a facile "potassium‐ions assisted" strategy is proposed to synthesize highly crystallized PBAs. By manipulating the dominant crystal plane and suppressing vacancies, the as‐prepared PBAs exhibit increased redox potential resulting in high energy density up to ≈450 Wh kg−1, which is at the same level of the well‐known LiFePO4 cathodes for lithium‐ion batteries. Remarkably, unconventional highly‐reversible phase evolution and redox‐active pairs were identified by multiple in situ techniques for the first time. The preferred guest‐ion storage sites and migration mechanism were systematically analysed through theoretical calculations. We believe these results could inspire the design of safe with high energy density. [ABSTRACT FROM AUTHOR]

Review: [100 refs. [ABSTRACT FROM AUTHOR]

Transition metal nitrides (TMNs) have great potential use in energy storage and conversion owing to tunable electronic and bonding characteristics. Novel iron rich nitrides nanoparticles anchored on the N‐doped porous carbon, named as (CoxFe1–x)3N@NPC (0 ≤ x < 0.5) are designed here. The synergistic effects of phase transition and electron‐spin regulation on oxygen electrocatalysis are testified. A core–shell structure of (CoxFe1–x)3N with high dispersibility is induced by an intermediate phase transition process, which significantly suppresses coarsening of the metallic nitrides. The Co incorporation regulates d‐band electrons spin polarization. The t2g5eg1 of FeII with the ideal eg electron filling boosts intrinsic activity. (Co0.17Fe0.83)3N@NPC with optimal cobalt content holds electronic configuration with moderate eg electron filling (t2g5eg1), which balances the adsorption of *O2 and the hydrogenation of *OH, improving bifunctional catalytic performances. Both liquid and solid‐state zinc–air batteries assembled based (Co0.17Fe0.83)3N@NPC cathodes substantially deliver higher peak power density and remarkable energy density. [ABSTRACT FROM AUTHOR]

Layered transition metal oxide (NaxTMO2), being one of the most promising cathode candidates for sodium‐ion batteries (SIBs), have attracted intensive interest because of their nontoxicity, high theoretical capacities, and easy manufacturability. However, their physical and electrochemical properties of water sensitivity, sluggish Na+ transport kinetics, and irreversible multiple‐phase translations hinder the practical application. Here, a concept of surface lattice‐matched engineering is proposed based on in situ spinel interfacial reconstruction to design a spinel coating P2/P3 heterostructure cathode material with enhanced air stability, rate, and cycle performance. The novel structure and its formation process are verified by transmission electron microscopy and in situ high‐temperature X‐ray diffraction. The electrode exhibits an excellent rate performance with the highly reversible phase transformation demonstrated by in situ charging/discharging X‐ray diffraction. Additionally, even after a rigorous water sensitivity test, the electrode materials still retain almost the same superior electrochemical performance as the fresh sample. The results show that the surface spinel phase can play a vital role in preventing the ingress of water molecules, improving transport kinetics, and enhancing structural integrity for NaxTMO2 cathodes. The concept of surface lattice‐matched engineering based on in situ spinel interfacial reconstruction will be helpful for designing new ultra‐stable cathode materials for high‐performance SIBs. [ABSTRACT FROM AUTHOR]

Abstract: Potassium‐ion batteries (PIBs) are promising energy storage systems because of the abundance and low cost of potassium. The formidable challenge is to develop suitable electrode materials and electrolytes for accommodating the relatively large size and high activity of potassium. Herein, Bi‐based materials are reported as novel anodes for PIBs. Nanostructural design and proper selection of the electrolyte salt have been used to achieve excellent cycling performance. It is found that the potassiation of Bi undergoes a solid‐solution reaction, followed by two typical two‐phase reactions, corresponding to Bi ↔ Bi(K) and Bi(K) ↔ K5Bi4 ↔ K3Bi, respectively. By choosing potassium bis(fluorosulfonyl)imide (KFSI) to replace potassium hexafluorophosphate (KPF6) in carbonate electrolyte, a more stable solid electrolyte interphase layer is achieved and results in notably enhanced electrochemical performance. More importantly, the KFSI salt is very versatile and can significantly promote the electrochemical performance of other alloy‐based anode materials, such as Sn and Sb. [ABSTRACT FROM AUTHOR]

Commercial 18650 lithium ion cells containing a blended positive electrode of layered LiNi 0.5 Mn 0.3 Co 0.2 O 2 and spinel Li 1.1 Mn 1.9 O 4 alongside a graphite negative electrode were stored at various depth-of-discharge (DoD) at 60 °C for 1, 2, 4, and 6 months. After storage, the cells were cycled at C/25 at 25 °C between 2.75 and 4.2 V for capacity determination and incremental capacity analysis (ICA). In addition to ICA analysis, the mechanism for capacity fade was investigated by combining the results of neutron powder diffraction under in-situ and operando conditions, in conjunction with post-mortem studies of the electrodes using synchrotron X-ray powder diffraction and inductively-coupled plasma optical emission spectroscopy. Among the cells, those stored at 25% DoD suffered the highest capacity fade due to their higher losses of active Li, NMC, and LMO than cells stored at other DoD. The cells stored at 0% DoD shows second high capacity fade because they exhibit the highest of active LMO and graphite anode among the stored cells and higher losses of active Li and NMC than cells stored at 50% DoD. [ABSTRACT FROM AUTHOR]

Cation migration often occurs in layered oxide cathodes of lithium‐ion batteries due to the similar ion radius of Li and transition metals (TMs). Although Na and TM show a big difference of ion radius, TMs in layered cathodes of sodium‐ion batteries (SIBs) can still migrate to Na layer, leading to serious electrochemical degeneration. To elucidate the origin of TM migration in layered SIB cathodes, we choose NaCrO2, a typical layered cathode suffering from serious TM migration, as a model material and find that the TM migration is derived from the random desodiation and subsequent formation of Na‐free layer at high charge potential. A Ru/Ti co‐doping strategy is developed to address the issue, where the doped active Ru is first oxidized to create a selective desodiation and the doped inactive Ti can function as a pillar to avoid complete desodiation in Ru‐contained TM layers, leading to the suppression of the Na‐free layer formation and subsequent enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Cation migration often occurs in layered oxide cathodes of lithium‐ion batteries due to the similar ion radius of Li and transition metals (TMs). Although Na and TM show a big difference of ion radius, TMs in layered cathodes of sodium‐ion batteries (SIBs) can still migrate to Na layer, leading to serious electrochemical degeneration. To elucidate the origin of TM migration in layered SIB cathodes, we choose NaCrO2, a typical layered cathode suffering from serious TM migration, as a model material and find that the TM migration is derived from the random desodiation and subsequent formation of Na‐free layer at high charge potential. A Ru/Ti co‐doping strategy is developed to address the issue, where the doped active Ru is first oxidized to create a selective desodiation and the doped inactive Ti can function as a pillar to avoid complete desodiation in Ru‐contained TM layers, leading to the suppression of the Na‐free layer formation and subsequent enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

The application of Li‐rich layered oxides is hindered by their dramatic capacity and voltage decay on cycling. This work comprehensively studies the mechanistic behaviour of cobalt‐free Li1.2Ni0.2Mn0.6O2 and demonstrates the positive impact of two‐phase Ru doping. A mechanistic transition from the monoclinic to the hexagonal behaviour is found for the structural evolution of Li1.2Ni0.2Mn0.6O2, and the improvement mechanism of Ru doping is understood using the combination of in operando and post‐mortem synchrotron analyses. The two‐phase Ru doping improves the structural reversibility in the first cycle and restrains structural degradation during cycling by stabilizing oxygen (O2−) redox and reducing Mn reduction, thus enabling high structural stability, an extraordinarily stable voltage (decay rate <0.45 mV per cycle), and a high capacity‐retention rate during long‐term cycling. The understanding of the structure‐function relationship of Li1.2Ni0.2Mn0.6O2 sheds light on the selective doping strategy and rational materials design for better‐performance Li‐rich layered oxides. [ABSTRACT FROM AUTHOR]

The application of Li‐rich layered oxides is hindered by their dramatic capacity and voltage decay on cycling. This work comprehensively studies the mechanistic behaviour of cobalt‐free Li1.2Ni0.2Mn0.6O2 and demonstrates the positive impact of two‐phase Ru doping. A mechanistic transition from the monoclinic to the hexagonal behaviour is found for the structural evolution of Li1.2Ni0.2Mn0.6O2, and the improvement mechanism of Ru doping is understood using the combination of in operando and post‐mortem synchrotron analyses. The two‐phase Ru doping improves the structural reversibility in the first cycle and restrains structural degradation during cycling by stabilizing oxygen (O2−) redox and reducing Mn reduction, thus enabling high structural stability, an extraordinarily stable voltage (decay rate <0.45 mV per cycle), and a high capacity‐retention rate during long‐term cycling. The understanding of the structure‐function relationship of Li1.2Ni0.2Mn0.6O2 sheds light on the selective doping strategy and rational materials design for better‐performance Li‐rich layered oxides. [ABSTRACT FROM AUTHOR]

Li-rich metal oxides, regarded as a high-voltage composite cathode, is currently one of the hottest positive electrode material for lithium-ion batteries, due to its high-capacity and high-energy performance. The crystallography, phase composition and morphology can be altered by synthesis parameters, which can influence drastically the capacity and cycling performance. In this work, we demonstrate Li 1.207 Ni 0.127 Mn 0.54 Co 0.127 O 2 , obtained by a co-precipitation method, exhibits super-high specific capacity up to 298 mAh g −1 and excellent capacity retention of ∼100% up to 50 cycles. Using neutron powder diffraction and transmission X-ray microscopy, we have found that the cooling-treatments applied after sintering during synthesis are crucially important in controlling the phase composition and morphology of the cathodes, thereby influencing the electrochemical performance. Unique spherical microstructure, larger lattice, and higher content of Li-rich monoclinic component can be achieved in the rapid quenching process, whereas severe particle cracking along with the smaller lattice and lower monoclinic component content is obtained when natural cooling of the furnace is applied. Combined with electrochemical impedance spectra, a plausible mechanism is described for the poorer specific capacity and cycling stability of the composite cathodes. [ABSTRACT FROM AUTHOR]

Alloy-based materials (i.e. Sn, Sb, P) are promising candidates for sodium-ion battery (SIB) anodes, but they suffer from capacity decay during charge/discharge cycling due to the pulverization caused by their huge volume change. Nanostructures can slow down the capacity fade, but most of the synthesis methods of such nanostructured anodes are difficult to scale-up. Herein, a ternary Sn 5 SbP 3 /C composite was fabricated by a green, low cost, one-step and easily scalable ball-milling of elementary Sn, Sb, P, and C. The microstructure of the ball-milled powders consists of micrometric agglomerates of active nano Sn 4 P 3 and SnSb and Sn particles. Carbon in the composite acts as a conducting matrix, and it does not only benefit to the ball milling efficiency, but also benefit to the cycle life of the electrode. Each of the active Sn 4 P 3 and SnSb and Sn phases in the composite functions mutually as a buffer for the others. As a result, this ternary composite anode delivers a good capacity of 352 mA h g −1 at the current density of 2 A g −1 , which is notably higher than that of the binary Sn 4 P 3 /C and SnSb/C composites produced under the same conditions. [ABSTRACT FROM AUTHOR]

Oxides composed of an oxygen framework and interstitial cations are promising cathode materials for lithium‐ion batteries. However, the instability of the oxygen framework under harsh operating conditions results in fast battery capacity decay, due to the weak orbital interactions between cations and oxygen (mainly 3d–2p interaction). Here, a robust and endurable oxygen framework is created by introducing strong 4s–2p orbital hybridization into the structure using LiNi0.5Mn1.5O4 oxide as an example. The modified oxide delivers extraordinarily stable battery performance, achieving 71.4 % capacity retention after 2000 cycles at 1 C. This work shows that an orbital‐level understanding can be leveraged to engineer high structural stability of the anion oxygen framework of oxides. Moreover, the similarity of the oxygen lattice between oxide electrodes makes this approach extendable to other electrodes, with orbital‐focused engineering a new avenue for the fundamental modification of battery materials. [ABSTRACT FROM AUTHOR]

Oxides composed of an oxygen framework and interstitial cations are promising cathode materials for lithium‐ion batteries. However, the instability of the oxygen framework under harsh operating conditions results in fast battery capacity decay, due to the weak orbital interactions between cations and oxygen (mainly 3d–2p interaction). Here, a robust and endurable oxygen framework is created by introducing strong 4s–2p orbital hybridization into the structure using LiNi0.5Mn1.5O4 oxide as an example. The modified oxide delivers extraordinarily stable battery performance, achieving 71.4 % capacity retention after 2000 cycles at 1 C. This work shows that an orbital‐level understanding can be leveraged to engineer high structural stability of the anion oxygen framework of oxides. Moreover, the similarity of the oxygen lattice between oxide electrodes makes this approach extendable to other electrodes, with orbital‐focused engineering a new avenue for the fundamental modification of battery materials. [ABSTRACT FROM AUTHOR]

Construction of porous surface, decoration of metal oxide, and introduction of defects are three major strategies to improve the electrocatalytic capability of graphite felt (GF) for vanadium redox flow battery (VRFB). In this study, we have successfully achieved the urea-assisted deposition of TiO 2 onto GF, resulting in a synergistic effect that realizes the three modifications mentioned above, through a facile one-pot approach. During the post-annealing process, the decorated TiO 2 can further undergo carbon-thermal reduction to etch the GF surface, leading to a porous surface. Additionally, the defective structures such as oxygen defects and nitrogen doping also be can simultaneously incorporated in the modified GF. As a result, the modified GF shows a dramatically improved electrocatalytic capability towards the VO2+/VO 2 + redox reactions due to better hydrophilicity, larger surface area, and numerous oxygen defects. The VRFB with the modified GF electrode can deliver the coulombic efficiency (CE), voltage efficiency (VE), and energy efficiency (EE) of 95.0, 81.8, and 77.8 %, respectively, at 160 mA/cm2, which are much better than those of VRFB based on untreated GF. • The modified GF electrodes with a synergistic effect of surface modification have been prepared. • The carbon-thermal reduction of TiO 2 can form porous structure on the GF electrode. • The modified GF reveals higher surface area, improved hydrophilicity and electrochemical resistance. • The VRFB using the modified GF electrode shows a great energy efficiency of 83.3 % at 100 mA/cm2. [ABSTRACT FROM AUTHOR]

Abstract: V-substituted LiFePO4 (LiFe1−x V x PO4, 0 ≤ x ≤ 0.10) powders are prepared via a solution method. The compositions, crystalline structure, morphology of the prepared powders are systemically investigated with inductive couple plasma-option emission spectrometry (ICP-OES), synchrotron radiation X-ray diffraction (s-XRD), X-ray Absorption Spectroscopy (XAS) and field emission-transmission electron microscopy (FE-TEM). Results of s-XRD and Rietveld analysis reveal that olivine phase is observed exclusively for LiFe1−x V x PO4 (x ≤ 0.05) samples, whereas a minor amount of monoclinic Li3V2(PO4)3 is detected in the prepared LiFe0.93V0.07PO4 and LiFe0.90V0.10PO4 samples. It is also found that the lattice parameters of olivine structure and average Li–O and M–O (M = Fe or V) bond lengths slightly increase and decrease with the amount of V substitution, recommending an enhanced lithium diffusivity in the structure. Results of XAS study suggest that V ions occupy octahedral sites (4c) of Fe in LiFePO4 structure with valence of 3+, showing good agreement with shortened M–O bonds determined in Rietveld analysis. As a result of V substitution, LiFe1−x V x PO4, (0 ≤ x ≤ 0.10) cathodes exhibit better electrochemical performance, such as discharge capacity, rate capability, and cycling performance at both room and elevated temperatures. [Copyright &y& Elsevier]

In this study, Li3V2(1-x)Fe3x(PO4)3 (0 ≤ x ≤ 0.09) powders are prepared via a solution method and heattreated at 700 °C for 8 hours. The chemical composition, morphology, crystalline structure, and valence of iron in the prepared samples were investigated with ICP, SEM, XRD, and EXAFS. The effects of Fe-substitution for vanadium sites on the electrochemical properties as cathode materials for lithium ion batteries are studied with capacity retention study and incremental capacity analysis. In addition to the monoclinic Li3V2(PO4)3 phase, olivine LiFePO4 is also observed when x ≥ 0.03. The valence of iron in the prepared powders is predominately 3+ at low substitution level (x ≤ 0.05), while the ratio of the Fe2+ to Fe3+ increases abruptly when the substitution level is higher than x = 0.07. Among the prepared samples, Li3V1.86Fe0.21(PO4)3 shows the best cycling performance at rates higher than 1C. It demonstrates discharge capacities of 141.2 mAh/g for second cycle and 126 mAh/g after 30 cycles at 5C rate. [ABSTRACT FROM AUTHOR]

Challenges from the insulating S and Li2S2/Li2S (Li2S1–2) discharge products are restricting the development of the high‐energy‐density Li–S battery system. The deposition of insulating Li2S1–2 on the surfaces of S based cathodes (e.g., S and Li2S) limits the reaction kinetics, leading to inferior electrochemical performance. In this work, the impact of binders on the deposition of Li2S1–2 on S based cathodes is revealed, along with the interaction between polyvinylidene difluoride and Li2S/polysulfides. This interaction can obstruct the electrochemical reactions near the binder, leading to dense deposition of insulating Li2S1–2 that covers the cathode surface. Without such a binder, localized and uniform Li2S1–2 deposition throughout the whole cathode can be achieved, effectively avoiding surface blockage and significantly improving electrode utilization. A full battery constructed with a binder‐free Li2S cathode delivers a gravimetric and volumetric energy density of 331.0 Wh kg−1 and 281.5 Wh L−1, under ultrahigh Li2S loading (16.2 mgLi2S cm−2) with lean electrolyte (2.0 µL mgLi2S−1), providing a facile but practical approach to the design of next‐generation S‐based batteries. [ABSTRACT FROM AUTHOR]

2D non‐layered metal sulfides possess intriguing properties, rendering them bright application prospects in energy storage and conversion, however, the synthesis of non‐layered metal sulfide nanosheets is still significantly challenging. Herein, a surface‐charge‐regulating strategy is developed to fabricate microsized 2D non‐layered metal sulfides via manipulation of the isoelectric point, which can easily modulate the manner of surface charge arrangement during the growth of crystal nuclei. The result of this strategy are materials that are completely assembled with a preferred orientation but comprise a large lateral size with maintaining atomic thickness. A series of modified sulfides are successfully synthesized, demonstrating that their microarchitectures are shifted in an expected manner. Then, one of these materials, In4SnS8, approaches a promising candidate for sodium storage by means of its structural integrity, boosted transfer kinetics, and abundant active sites. The proposed synthetic protocol can open up a new opportunity to explore 2D non‐layered materials for energy‐related applications. [ABSTRACT FROM AUTHOR]

The design and manufacture of advanced materials based on biomaterials provide new opportunities to solve many technological challenges. In this work, a highly graphitized wood framework (GWF) with a porous tunnel structure and microvilli is constructed as a multifunctional interlayer to improve the electrochemical performance of lithium–sulfur (Li–S) batteries. The GWF not only retains the 3D transport network of wood, but also offers increased deposition sites for polysulfides through the microvilli which grow on the inner surfaces of the carbon tunnels. Electrochemical tests show that GWF effectively enhances the initial discharge capacity of the Li–S battery to 1593 mAh g−1 at 0.05 C, with a low capacity decline of 0.06% per cycle at 1 C. Besides, the GWF interlayer also effectively protects lithium anodes from corrosion by Sx2−, thus they still keep their metallic luster and clean surface even after long charge‐discharge cycles. These enhancements are attributed to the high conductivity, abundant microvilli, and tunnel confinement effects of GWF, which effectively inhibit the shuttle effect of polysulfides by the same principle as nose hairs filtering the air. This work presents a new understanding of bionic/biomaterials and a new strategy to improve the performance of Li–S batteries. [ABSTRACT FROM AUTHOR]

Significant interest is directed towards converting CO 2 to high-value feedstock chemicals. Here, the performance of carbon deposited from carbonate fluxes under CO 2 environments are reported for direct use as anodes in sodium-ion batteries. The generated carbon is found to be amorphous hard carbon, evidenced by X-ray diffraction (XRD) data and I D /I G ratios of the D- and G- bands of graphite in Raman spectroscopy. Furthermore, the role of washing and removing the deposit is evaluated for the carbon generated and the subsequent electrochemical performance. The best performing samples were grown on a copper substrate, which delivered initial reversible capacities of 209 ± 23 mAh/g mAh/g on the 5th cycle at a rate of 10 mA/g, and feature a capacity retention of 86.6 ± 1.8 % after 50 cycles. The value in this approach to generate carbons lies in the fact that these fluxes are designed to be similar to that used for molten salts in solar thermal plants and, if coupled appropriately to CO 2 sources, they can be used to convert CO 2 into carbons. A model system is proposed on how this can be achieved to possibly produce a carbon negative anode for sodium-ion batteries, with potential for an overall carbon negative sodium-ion battery. [ABSTRACT FROM AUTHOR]

Elucidating the battery operating mechanism is important for designing better conversion‐type anodes as it determines the strategies used to improve electrochemical performances. Herein, the authors pioneered the electrochemical study of layered Bi2O2Se as anodes for lithium‐ion batteries (LIBs) and potassium‐ion batteries (PIBs). Surprisingly, the Bi2O2Se/graphite composite electrode shows even better cycle stability for PIBs. The electrochemical reaction mechanisms of the Bi2O2Se/graphite electrode for LIBs and PIBs are investigated by potential‐resolved in situ and ex situ X‐ray absorption spectroscopy based at the Bi LIII‐edge and Se K‐edge through characterizing the local atomic structure evolution, valence state change, and charge transfer. New insights are gained regarding the electrochemical process of Se2− anions in Bi2O2Se, where multiple Li–Se intermediates rather than the traditional single‐phase Li2Se are involved in this conversion‐type anode. The advanced understanding of anionic electrochemistry in conversion‐type anodes prompts one to find appropriate ways to suppress side‐reactions and improve the battery performances. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries (PIBs) are an emerging, affordable, and environmentally friendly alternative to lithium‐ion batteries, with their further development driven by the need for suitably performing electrode materials capable of reversibly accommodating the relatively large K+. Layer‐structured manganese oxides are attractive as electrodes for PIBs, but suffer from structural instability and sluggish kinetics of K+ insertion/extraction, leading to poor rate capability. Herein, cobalt is successfully introduced at the manganese site in the KxMnO2 layered oxide electrode material and it is shown that with only 5% Co, the reversible capacity increases by 30% at 22 mA g‐1 and by 92% at 440 mA g‐1. In operando synchrotron X‐ray diffraction reveals that Co suppresses Jahn–Teller distortion, leading to more isotropic migration pathways for K+ in the interlayer, thus enhancing the ionic diffusion and consequently, rate capability. The detailed analysis reveals that additional phase transitions and larger volume change occur in the Co‐doped material as a result of layer gliding, with these associated with faster capacity decay, despite the overall capacity remaining higher than the pristine material, even after 500 cycles. These results assert the importance of understanding the detailed structural evolution that underpins performance that will inform the strategic design of electrode materials for high‐performance PIBs. [ABSTRACT FROM AUTHOR]

Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode candidate for the next‐generation high energy‐density lithium‐ion batteries (LIBs). Unfortunately, the application of LNMO is hindered by its poor cycle stability. Now, site‐selectively doped LNMO electrode is prepared with exceptional durability. In this work, Mg is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in the Fd3‾ m structure. This site‐selective doping not only suppresses unfavorable two‐phase reactions and stabilizes the LNMO structure against structural deformation, but also mitigates the dissolution of Mn during cycling. Mg‐doped LNMOs exhibit extraordinarily stable electrochemical performance in both half‐cells and prototype full‐batteries with novel TiNb2O7 counter‐electrodes. This work pioneers an atomic‐doping engineering strategy for electrode materials that could be extended to other energy materials to create high‐performance devices. [ABSTRACT FROM AUTHOR]

Spinel LiNi0.5Mn1.5O4 (LNMO) is a promising cathode candidate for the next‐generation high energy‐density lithium‐ion batteries (LIBs). Unfortunately, the application of LNMO is hindered by its poor cycle stability. Now, site‐selectively doped LNMO electrode is prepared with exceptional durability. In this work, Mg is selectively doped onto both tetrahedral (8a) and octahedral (16c) sites in the Fd3‾ m structure. This site‐selective doping not only suppresses unfavorable two‐phase reactions and stabilizes the LNMO structure against structural deformation, but also mitigates the dissolution of Mn during cycling. Mg‐doped LNMOs exhibit extraordinarily stable electrochemical performance in both half‐cells and prototype full‐batteries with novel TiNb2O7 counter‐electrodes. This work pioneers an atomic‐doping engineering strategy for electrode materials that could be extended to other energy materials to create high‐performance devices. [ABSTRACT FROM AUTHOR]

Ultrathin few‐layer materials have attracted intensive research attention because of their distinctive and unique properties. Few‐layer GeP (FL‐GP) is potentially interesting for application in electronics and optoelectronics because of its appropriate band gap and good stability under ambient conditions. Nevertheless, it is a challenge to achieve ultrathin few‐layer or single layer GeP from exfoliation of bulk crystals. Here, a lithiation‐assisted chemical exfoliation technique is employed to achieve FL‐GP, in which the interlayer spacing can be efficiently enlarged after a preliminary lithium ion intercalation, allowing the bulk crystal to be readily exfoliated in a following ultrasonication. As a result, ultrathin FL‐GP is obtained. In a demonstration, the FL‐GP/reduced graphene oxide (rGO) demonstrates remarkable sodium storage performance. The FL‐GP with a two‐dimensional structure shortens the ion transport pathways and alleviates the volume variation during sodiation. Meanwhile, the rGO in the composite improves the conductivity of the whole electrode. The as‐prepared FL‐GP/rGO electrode exhibits a high capacity of 504.2 mAh g−1 at 100 mA g−1, remarkable rate performance, and superior cycling stability in the half cells. FL‐GP/rGO//Na3V2(PO4)3 full cells are also assembled and demonstrated satisfactory electrochemical performance, indicating potential application of the as‐prepared anode materials. [ABSTRACT FROM AUTHOR]

Lithium‐rich layered oxides are promising candidate cathode materials for the Li‐ion batteries with energy densities above 300 Wh kg−1. However, issues such as the voltage hysteresis and decay hinder their commercial applications. Due to the entanglement of the transition metal (TM) migration and the anionic redox upon lithium extraction at high potentials, it is difficult to recognize the origin of these issues in conventional Li‐rich layered oxides. Herein, Li2MoO3 is chosen since prototype material to uncover the reason for the voltage hysteresis as the TM migration and anionic redox can be eliminated below 3.6 V versus Li+/Li in this material. On the basis of comprehensive investigations by neutron powder diffraction, scanning transmission electron microscopy, synchrotron X‐ray absorption spectroscopy, and density functional theory calculations, it is clarified that the ordering–disordering transformation of the Mo3O13 clusters induced by the intralayer Mo migration is responsible for the voltage hysteresis in the first cycle; the hysteresis can take place even without the anionic redox or the interlayer Mo migration. A similar suggestion is drawn for its iso‐structured Li2RuO3 (C2/c). These findings are useful for understanding of the voltage hysteresis in other complicated Li‐rich layered oxides. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries are promising for low‐cost and large‐scale energy storage applications, but the major obstacle to their application is the lack of safe and effective electrolytes. A phosphate‐based fire retardant such as triethyl phosphate is now shown to work as a single solvent with potassium bis(fluorosulfonyl)imide at 0.9 m, in contrast to previous Li and Na systems where phosphates cannot work at low concentrations. This electrolyte is optimized at 2 m, where it exhibits the advantages of low cost, low viscosity, and high conductivity, as well as the formation of a uniform and robust salt‐derived solid‐electrolyte interphase layer, leading to non‐dendritic K‐metal plating/stripping with Coulombic efficiency of 99.6 % and a highly reversible graphite anode. [ABSTRACT FROM AUTHOR]

Potassium‐ion batteries are promising for low‐cost and large‐scale energy storage applications, but the major obstacle to their application is the lack of safe and effective electrolytes. A phosphate‐based fire retardant such as triethyl phosphate is now shown to work as a single solvent with potassium bis(fluorosulfonyl)imide at 0.9 m, in contrast to previous Li and Na systems where phosphates cannot work at low concentrations. This electrolyte is optimized at 2 m, where it exhibits the advantages of low cost, low viscosity, and high conductivity, as well as the formation of a uniform and robust salt‐derived solid‐electrolyte interphase layer, leading to non‐dendritic K‐metal plating/stripping with Coulombic efficiency of 99.6 % and a highly reversible graphite anode. [ABSTRACT FROM AUTHOR]

Abstract: As an emerging electrochemical energy storage device, potassium‐ion batteries (PIBs) have drawn growing interest due to the resource‐abundance and low cost of potassium. Graphite‐based materials, as the most common anodes for commercial Li‐ion batteries, have a very low capacity when used an anode for Na‐ion batteries, but they show reasonable capacities as anodes for PIBs. The practical application of graphitic materials in PIBs suffers from poor cyclability, however, due to the large interlayer expansion/shrinkage caused by the intercalation/deintercalation of potassium ions. Here, a highly graphitic carbon nanocage (CNC) is reported as a PIBs anode, which exhibits excellent cyclability and superior depotassiation capacity of 175 mAh g−1 at 35 C. The potassium storage mechanism in CNC is revealed by cyclic voltammetry as due to redox reactions (intercalation/deintercalation) and double‐layer capacitance (surface adsorption/desorption). The present results give new insights into structural design for graphitic anode materials in PIBs and understanding the double‐layer capacitance effect in alkali metal ion batteries. [ABSTRACT FROM AUTHOR]

Electrocatalysis, electron-spin regulation, phase transition, transition metal nitrides Synergistic Effects of Phase Transition and Electron-Spin Regulation on the Electrocatalysis Performance of Ternary Nitride (Adv. Funct. Keywords: electrocatalysis; electron-spin regulation; phase transition; transition metal nitrides EN electrocatalysis electron-spin regulation phase transition transition metal nitrides 1 1 1 06/22/23 20230619 NES 230619 B Phase Transitions b The synergistic effects of phase transition and electron-spin regulation boosts oxygen electrocatalysis. [Extracted from the article]

Surface Lattice-Matched Engineering Based on In Situ Spinel Interfacial Reconstruction for Stable Heterostructured Sodium Layered Oxide Cathodes (Adv. Funct. Keywords: air stability; heterostructures; layered oxide cathodes; sodium-ion batteries; spinel engineering EN air stability heterostructures layered oxide cathodes sodium-ion batteries spinel engineering 1 1 1 04/06/23 20230404 NES 230404 B Layered Oxide Cathodes b In article number 2213215, Yao Xiao, Shu-Lei Chou, Jia-Zhao Wang, Yan-Fang Zhu, and co-workers propose a concept of surface lattice-matched engineering based on in-situ spinel interfacial reconstruction to design a spinel coating P2/P3 heterostructure cathode material with enhanced air stability, rate, and cycle performance. Air stability, heterostructures, layered oxide cathodes, sodium-ion batteries, spinel engineering. [Extracted from the article]

Ex situ and time-resolved in operando neutron powder diffraction (NPD) has been used to study the structural evolution of the graphite negative electrode and LiFePO 4 positive electrode within ANR26650M1A commercial batteries from A123 Systems, in what to our knowledge is the first reported NPD study investigating a 26650-type battery. Batteries with different and accurately-known electrochemical and storage histories were studied, enabling the tell-tale signs of battery degradation to be elucidated using NPD. The ex-situ NPD data revealed that the intensity of the graphite/lithiated graphite (Li x C 6 or Li y C) reflections was affected by battery history, with lower lithiated graphite (LiC 12 ) reflection intensities typically corresponding to more abused batteries. This indicates that the lithiation of graphite is less progressed in more abused batteries, and hence these batteries have lower capacities. In operando NPD allows the rate of structural evolution in the battery electrode materials to be correlated to the applied current. Interestingly, the electrodes exhibit different responses to the applied current that depend on the battery cycling history, with this particularly evident for the negative electrode. Therefore, this work illustrates how NPD can be used to correlate a battery history with electrode structure. [ABSTRACT FROM AUTHOR]

The application of detailed in-situ neutron diffraction studies on lithium ion batteries has been limited in part due to the requirement of expensive deuterated carbonate-based electrolyte. This work presents an in-situ neutron diffraction study of the structural evolution of the Li x (Ni 0.4 Mn 0.4 Co 0.2 )O 2 (NMC442) positive electrode material using a recently-developed low-cost deuterated ethyl acetate-based electrolyte. Rietveld analysis show that the NMC442 c lattice parameter gradually increases until x = 0.47 (4.03 V) and then decreases during the first charge. The decreasing trend of the c lattice parameter with time during the hold at 4.7 V and 4.9 V agrees very well with the change of current. Overall the structural changes appear highly reversible when 4.7 V is used as an upper cutoff voltage, even following a 10 h hold at 4.7 V. However, the electrode/electrolyte changes dramatically when charged and held at 4.9 V. There is a significant drop in background attributed to electrolyte decomposition and an unexpected increase in the a lattice parameter is noted after the 4.9 V hold. Therefore, the electrolyte system used is both beneficial for in-situ neutron diffraction studies and battery performance until 4.7 V, but appears to degrade in combination with the electrode at 4.9 V. By comparison to Li(Ni 0.8 Mn 0.1 Co 0.1 )O 2 (NMC811), the contraction of the c lattice with increasing voltage and decreasing lithium content of the NMC442 is less rapid. The transition metal composition significantly affects the c lattice contraction above 4.0 V. [ABSTRACT FROM AUTHOR]

A low-cost deuterated electrolyte suitable for in situ neutron diffraction measurements of normal and high voltage Li-ion battery electrodes is reported here. Li[Ni 0.4 Mn 0.4 Co 0.2 ]O 2 /graphite (NMC(442)/graphite) pouch cells filled with 1:0.1:2 (molar ratio) of lithium bis(fluorosulfonyl) imide (LiFSi):LiPF 6 : ethyl acetate (EA) and LiFSi:LiPF 6 :deuterated EA (d8-EA) electrolytes were successfully cycled between 2.8 V and 4.7 V at 40°C for 250 h without significant capacity loss, polarization growth, or gas production. The signal-to-noise ratio of neutron powder diffraction patterns taken on NMC(442) powder with a conventional deuterated organic carbonate-based electrolyte and filled with LiFSi:LiPF 6 :d8-EA electrolyte were virtually identical. Out of all the solvents widely available in deuterated form tested in highly-concentrated systems, EA was the only one providing a good balance between cost and charge-discharge capacity retention to 4.7 V. The use of such an electrolyte blend would half the cost of deuterated solvents needed for in situ neutron diffraction measurements of Li-ion batteries compared to conventional deuterated carbonate-based electrolytes. [ABSTRACT FROM AUTHOR]

The development of new insertion electrodes in sodium-ion batteries requires an in-depth understanding of the relationship between electrochemical performance and the structural evolution during cycling. To date in situ synchrotron X-ray and neutron diffraction methods appear to be the only probes of in situ electrode evolution at high rates, a critical condition for battery development. Here, the structural evolution of the recently synthesized O3-phase of Na2/3Fe2/3Mn1/3O2 is reported under relatively high current rates. The evolution of the phases, their lattice parameters, and phase fractions, and the sodium content in the crystal structure as a function of the charge/discharge process are shown. It is found that the O3-phase persists throughout the charge/discharge cycle but undergoes a series of two-phase and solid-solution transitions subtly modifying the sodium content and atomic positions but keeping the overall space-group symmetry (structural motif). In addition, for the first time, evidence of a structurally characterized region is shown that undergoes two-phase and solid-solution phase transitions simultaneously. The Mn/Fe-O bond lengths, c lattice parameter evolution, and the distance between the Mn/FeO6 layers are shown to concertedly change in a favorable manner for Na+ insertion/extraction. The exceptional electrochemical performance of this electrode can be related in part to the electrode maintaining the O3-phase throughout the charge/discharge process. [ABSTRACT FROM AUTHOR]

Oxides composed of an oxygen framework and interstitial cations are promising cathode materials for lithium‐ion batteries. However, the instability of the oxygen framework under harsh operating conditions results in fast battery capacity decay, due to the weak orbital interactions between cations and oxygen (mainly 3d–2p interaction). Here, a robust and endurable oxygen framework is created by introducing strong 4s–2p orbital hybridization into the structure using LiNi0.5Mn1.5O4 oxide as an example. The modified oxide delivers extraordinarily stable battery performance, achieving 71.4 % capacity retention after 2000 cycles at 1 C. This work shows that an orbital‐level understanding can be leveraged to engineer high structural stability of the anion oxygen framework of oxides. Moreover, the similarity of the oxygen lattice between oxide electrodes makes this approach extendable to other electrodes, with orbital‐focused engineering a new avenue for the fundamental modification of battery materials. [ABSTRACT FROM AUTHOR]

Abstract: Core–shell Li4Ti5O12@CeO2 nanosphere has been synthesized by a one-pot co-precipitation method. The structure and morphology of the as-prepared materials have been analyzed by X-ray diffraction and transmission electron microscopy. The results show that CeO2 is successfully coated on the surface of the Li4Ti5O12 besides partial doping of Ce4+ into the Li4Ti5O12 structure. The Li4Ti5O12@CeO2 nanosphere exhibits excellent capacity of 152 mAh g−1 even after 180 cycles at 10 C, with no noticeable capacity fading. Furthermore, the sample shows much improved rate capability at 40 C compared with pure Li4Ti5O12 when used as anode material for lithium-ion batteries. The introduction of CeO2 enhances not only the electric conductivity of Li4Ti5O12, but also the lithium ion diffusivity in Li4Ti5O12, resulting in significantly improved electrochemical performance of the Li4Ti5O12. [Copyright &y& Elsevier]