Reaction Of Anion Research Articles

Cumulative cationic and anionic redox reaction in Mg3V2(SiO4)3 and impact on the battery performance

A cumulative cationic and oxygen anionic redox reaction receives much attention for enhancing battery capacity in intercalant-excess cathode materials. However, such combinatorial electrochemical reactions are studied mostly for Li-containing cathode active materials so far, and multivalent systems remain unexplored from this perspective. Here, we examine the redox chemistry in the garnet-type Mg 3 V 2 (SiO 4 ) 3 based on first-principles density functional theory calculations. Our calculations demonstrate the occurrence of a cumulative reversible cationic and anionic redox reaction without additional magnesium atoms, which offers an average discharge voltage of 3.23 V vs. Mg/Mg 2+ with an energy density of as high as 1152 Wh/kg. Moreover, the unique three-dimensional corner-shared polyanionic framework in Mg 3 V 2 (SiO 4 ) 3 only provides marginal structural changes, unlike layered Li-rich cathodes, which implies that irreversible O 2 gas release is highly unlikely. Together with a low energy barrier for Mg migration, our finding provides a new insight to develop high-performance multivalent cathode active materials for which a cumulative cationic and oxygen anionic redox reaction plays an important role. • A reversible cationic and anionic redox is achievable with Mg x V 2 (SiO 4 ) 3 (0 ≤ x ≤ 3). • Three-dimensional corner-shared polyanionic framework retains minimal structural changes. • Low energy barrier for Mg-ion migration is obtained within V 2 (SiO 4 ) host.

Long-enduring oxygen redox enabling robust layered cathodes for sodium-ion batteries

Anionic redox chemistry has emerged as a promising pathway attracted extensively attention to meet the demands of high energy sodium-ion batteries. Nonetheless, suchlike cathode materials suffer from poor reversible oxygen redox reactions leading to severe capacity degradation along with sluggish kinetics and voltage decay. In this work, layered sodium transition metal oxides Na0.67Mg0.28Mn0.72-xRuxO2 (x = 0–0.6) are presented, where the optimized sample (x = 0.12) offers an attractively sustainable capacity of 222 mAh g−1 and a distinguished rate capability of 101.7 mAh g−1 at 50C, based on the anionic and cationic activity. The results reveal that the oxygen redox retention is endured at 94.1% in the optimized sample (x = 0.12) after 55 cycles, in contrast to 48.9% of the pristine sample (x = 0), which is the maximum value reported up to now. Meanwhile the lattice parameters show almost no variation, according to the in situ/ex situ X-ray diffraction experiments. Ru-substitution significantly improves the anionic redox reversibility, the structural stability and sodium diffusion, resulting in the noteworthy electrochemical performance advancement. The research performs an effective method to moderate the problems existing in anionic redox reactions and makes a reference for subsequent materials design.

Low-cost layered oxide cathode involving cationic and anionic redox with a complete solid-solution sodium-storage behavior

Iron/manganese-based layered transition-metal oxides have attracted numerous attentions as promising cathodes for sodium-ion batteries (SIBs) due to their high theoretical capacities and abundant reserves, yet they still suffer from detrimental phase transitions and fast capacity fading. Herein, we realize a complete solid-solution sodiation/desodiation behavior over a wide voltage range of 1.5–4.3 V in a novel P2-Na0.75Ca0.05Li0.15Fe0.2Mn0.6O2 (P2-NCLFMO) cathode material, where cationic and anionic redox reactions synergistically provide charge compensation. Li ions in transition-metal (TM) sites not only trigger the oxygen redox activity, but also increase the Na content for stabilizing the P2-structure at high voltage and weaken the Jahn-Teller effect by diluting the Mn3+ concentration; Ca ions in Na sites serve as “pillars” to stabilize the layered structure and alleviate the lattice oxygen release. The complete solid-solution reaction in the wide voltage range ensures both rapid Na+ diffusivity and small volume variation. Therefore, the P2-NCLFMO cathode shows outstanding rate capability (183 mAh g−1 at 0.1C in comparison with 49.9 mAh g−1 at 20C) and respectable cycling performance (76% capacity retention after 150 cycles at 1C). Additionally, the prototype Na-ion full battery constructed by the P2-NCLFMO cathode and hard carbon anode delivers a promising energy density of 246.3 Wh kg−1. This work provides a new platform for achieving high-energy and long-life layered oxide cathodes involving cationic and anionic redox by eliminating the irreversible phase transitions.

Enabling Anionic Redox Stability of P2-Na5/6 Li1/4 Mn3/4 O2 by Mg Substitution.

Oxygen-based anionic redox reactions have recently emerged as a lever to increase the capacity of Mn-rich layered oxide cathodes in addition to the charge compensation based on cationic redox reactions for sodium-ion batteries. Unfortunately, the irreversibility of anionic redox often aggravates irreversible structure change and poor cycling performance. Here, a stable anionic redox is achieved through substituting Na ions by Mg ions in P2-type Na0.83 Li0.25 Mn0.75 O2 . Density functional theory (DFT) calculations reveal that Mg substitution effectively decreases the oxygen chemical potential, causing an improvement in lattice oxygen stability. Moreover, at a highly desodiated state, Mg ions that remain in the lattice and interact with O 2p orbitals can decrease the undercoordinated oxygen and the nonbonded, electron-deficient O 2p states, facilitating the reversibility of oxygen redox. When cycled in the voltage range of 2.6-4.5V where only anionic redox occurs for charge compensation, Na0.773 Mg0.03 Li0.25 Mn0.75 O2 presents a much better reversibility, giving a 4 times better cycle stability than that of Na0.83 Li0.25 Mn0.75 O2 . Experimentally, Na0.773 Mg0.03 Li0.25 Mn0.75 O2 exhibits a ≈1.1% volume expansion during sodium insertion/extraction, suggestive of a "zero-strain" cathode. Overall, the work opens a new avenue for enhancing anionic reversibility of oxygen-related Mn-rich cathodes.

Adjusting Oxygen Redox Reaction and Structural Stability of Li- and Mn-Rich Cathodes by Zr-Ti Dual-Doping.

Li- and Mn-rich cathodes (LMRs) with cationic and anionic redox reactions are considered as promising cathode materials for high-energy-density Li-ion batteries. However, the oxygen redox process leads to lattice oxygen loss and structure degradation, which would induce serious voltage fade and capacity loss and thus limit the practical application. High-valent and electrochemical inactive d0 element doping is an effective method to tune the crystal and electronic structures, which are the main factors for the electrochemical stability. Herein, noticeably inhibited oxygen loss, reduced voltage fade, enhanced rate performance, and improved structure stability and thermal stability of LMRs have been realized by Ti4+ and Zr4+ dual-doping. The underlying modulation mechanisms are unraveled by combining differential electrochemical mass spectrometry, soft X-ray absorption spectroscopies, in situ XRD measurements, etc. The dual-doping reduces the covalency of the TM-O bond, mitigates the irreversible oxygen release during the oxygen redox, and stabilizes the layered framework. The expanded lithium layer facilitates the lithium diffusion kinetics and structure stability. This study may result in the fundamental understanding of crystal and electronic structure evolution in LMRs and contribute to the development of high capacity cathodes.

Ultrasound/chlorine sono-hybrid-advanced oxidation process: Impact of dissolved organic matter and mineral constituents

In this work, after exploring the first report on the synergism of combining ultrasound (US: 600 kHz) and chlorine toward the degradation of Allura Red AC (ARAC) textile dye, as a contaminant model, the impact of various mineral water constituents (Cl−, SO42−, NO3−, HCO3− and NO2−) and natural organic matter, i.e., humic acid (HA), on the performance of the US/chlorine sono-hybrid process was assessed for the first time. Additionally, the process effectiveness was evaluated in a real natural mineral water (NMW) of a known composition. Firstly, it was found that the combination of ultrasound and chlorine (0.25 mM) at pH 5.5 in cylindrical standing wave ultrasonic reactor (f = 600 kHz and Pe = 120 W, equivalent to PA ∼ 2.3 atm) enhanced in a drastic manner the degradation rate of ARAC; the removal rate being 320% much higher than the arithmetic sum of the two separated processes. The source of the synergistic effect was attributed to the effective implication of reactive chlorine species (RCS: Cl, ClO and Cl2−) in the degradation process. Radical probe technique using nitrobenzene (NB) as a specific quencher of the acoustically generated hydroxyl radical confirmed the dominant implication of RCS in the overall degradation rate of ARAC by US/chlorine system. Overall, the presence of humic acid and mineral anions decreased the efficiency of the sono-hybrid process; however, the inhibition degrees depend on the type and the concentration of the selected additives. The reaction of these additives with the generated RCS is presumably the reason for the finding results. The inhibiting effect of Cl−, SO42−, NO3− and NO2− was more pronounced in US/chlorine process as compared to US alone, whereas the inverse scenario was remarked for the effect of HA. These outcomes were associated to the difference in the reactivity of HA and mineral anions toward RCS and OH oxidizing species, in addition to the more selective character of RCS than hydroxyl radical. The displacement of the reaction zone with increasing the additive concentration may also be another influencing factor that favors competition reactions, which subsequently reduce the available reactive species in the reacting medium. The NMW exerted reductions of 43% and 10% in the process efficiency at pH 5.5 and 8, respectively, thereby confirming the RCS-quenching mechanism by the water matrix constituents. Hence, this work provided a precise understanding of the overall mechanism of chlorine activation by ultrasound to promote organic compounds degradation in water.

Unraveling Anionic Redox for Sodium Layered Oxide Cathodes: Breakthroughs and Perspectives.

Sodium-ion batteries (SIBs) as the next generation of sustainable energy technologies have received widespread investigations for large-scale energy storage systems (EESs) and smart grids due to the huge natural abundance and low cost of sodium. Although the great efforts are made in exploring layered transition metal oxide cathode for SIBs, their performances have reached the bottleneck for further practical application. Nowadays, anionic redox in layered transition metal oxides has emerged as a new paradigm to increase the energy density of rechargeable batteries. Based on this point, in this review, the development history of anionic redox reaction is attempted to systematically summarize and provide an in-depth discussion on the anionic redox mechanism. Particularly, the major challenges of anionic redox and the corresponding available strategies toward triggering and stabilizing anionic redox are proposed. Subsequently, several types of sodium layered oxide cathodes are classified and comparatively discussed according to Na-rich or Na-deficient materials. A large amount of progressive characterization techniques of anionic oxygen redox is also summarized. Finally, an overview of the existing prospective and the future development directions of sodium layered transition oxide with anionic redox reaction are analyzed and suggested.

A combined experimental and theoretical study on the reactivity of nitrenes and nitrene radical anions

Nitrene transfer reactions represent one of the key reactions to rapidly construct new carbon-nitrogen bonds and typically require transition metal catalysts to control the reactivity of the pivotal nitrene intermediate. Herein, we report on the application of iminoiodinanes in amination reactions under visible light photochemical conditions. While a triplet nitrene can be accessed under catalyst-free conditions, the use of a suitable photosensitizer allows the access of a nitrene radical anion. Computational and mechanistic studies rationalize the access and reactivity of triplet nitrene and nitrene radical anion and allow the direct comparison of both amination reagents. We conclude with applications of both reagents in organic synthesis and showcase their reactivity in the reaction with olefins, which underline their markedly distinct reactivity. Both reagents can be accessed under mild reaction conditions at room temperature without the necessity to exclude moisture or air, which renders these metal-free, photochemical amination reactions highly practical.

Boosting capacity and operating voltage of LiVO3 as cathode for lithium-ion batteries by activating oxygen reaction in the lattice

Capacity and operating voltage are critical parameters of cathode materials that dictate the energy density of lithium-ion batteries. Traditionally, redox reaction of the transition metal in the cathode limits the operating voltage and capacity during charge/discharge. Here, we simultaneously increase the capacity and operating voltage of LiVO 3 by utilizing the anionic redox reaction of oxygen in the lattice. While LiVO 3 gives a capacity of 235 mAh g −1 with an average potential of 2.18 V vs. Li/Li + between 1.5 and 3.0 V from the vanadium redox reaction, they increase to 358 mAh g −1 and 2.55 V vs. Li/Li + , respectively, between 1.5 and 4.8 V. The higher capacity and operating voltage are due to the extraction of 0.56 mol of Li from its lattice when charging it to 4.8 V, despite vanadium originally in its highest oxidation state of 5+. The additional charge transfer derives from oxygen in the material, as X-ray spectroscopies and density functional theory calculation demonstrate the presence of peroxide species in the material and spin density around oxygen atoms, respectively, upon lithium extraction. Structural and gas analyses further reveal the stability of the anionic reaction, with only 0.21% volume change during lithium extraction with no O 2 gas release. • Monoclinic LiVO 3 exhibits anionic redox reaction (ARR) by charging it to 4.8 V. • 0.56 mol of Li is extracted from LiVO 3 upon charging despite valence of V is 5+. • Structural change of LiVO 3 is negligible with ARR between 2.4 and 4.8 V. • LiVO 3 gives discharge capacity of 358 mAh g −1 between 1.5 and 4.8 V. • Effect of voltage range on electrochemical performance of LiVO 3 studied.

C(sp3)-H bond activation by the carboxylate-adduct of osmium tetroxide (OsO4).

The reaction of osmium tetroxide (OsO4) and carboxylate anions (acetate: X- = AcO- and benzoate: X- = BzO-) gave 1 : 1 adducts, [OsO4(X)]- (1X), the structures of which were determined by X-ray crystallographic analysis. In both cases, the carboxylate anion X coordinates to the osmium centre to generate a distorted trigonal bipyramidal osmium(VIII) complex. The carboxylate adducts show a negative shift of the redox potentials (E1/2) and a red shift of the νOsO stretches as compared to those of tetrahedral OsO4 itself. Despite the negative shift of E1/2, the reactivity of these adduct complexes 1X was enhanced compared to that of OsO4 in benzylic C(sp3)-H bond oxidation. The reaction obeyed the first-order kinetics on both 1X and the substrates, giving the second-order rate constant (k2), which exhibits a linear correlation with the C-H bond dissociation energy (BDEC-H) of the substrates (xanthene, 9,10-dihydroanthracene, fluorene and 1,2,3,4-tetrahydronaphthalene) and a kinetic deuterium isotope effect (KIE) of 9.7 (k2(xanthene-h2)/k2(xanthene-d2)). On the basis of these kinetic data together with the DFT calculation results, we propose a stepwise reaction mechanism involving rate-limiting benzylic hydrogen atom abstraction and subsequent rebound of the generated organic radical intermediate to a remaining oxido group on the osmium centre.

The hydroperoxyl antiradical activity of natural hydroxycinnamic acid derivatives in physiological environments: the effects of pH values on rate constants.

Hydroxycinnamic acid derivatives (HCA) are a type of phenolic acid that occurs naturally. HCA are widely known for their anti-inflammatory, anti-cancer, and especially antioxidant capabilities; however, a comprehensive study of the mechanism and kinetics of the antiradical activity of these compounds has not been performed. Here, we report a study on the mechanisms and kinetics of hydroperoxyl radical scavenging activity of HCA by density functional theory (DFT) calculations. The ability of HCA to scavenge hydroperoxyl radicals in physiological environments was studied. The results showed that HCA had moderate and weak HOO˙ antiradical activity in pentyl ethanoate solvent, with the overall rate constant koverall = 8.60 × 101 − 3.40 × 104 M−1 s−1. The formal hydrogen transfer mechanism of phenyl hydroxyl groups defined this action. However, in water at physiological pH, 2-coumaric acid (1), 4-coumaric acid (2), caffeic acid (3), ferulic acid (4), sinapic acid (5) and 4-hydroxyphenylpyruvic acid (7) exhibit a significant HOO˙ antiradical activity with ktotal = 105 − 108 M−1 s−1 by the electron transfer reaction of the phenolate anions. Following a rise in pH levels in most of the studied substances, the overall rate constant varied. The acid 5 exhibited the highest HOO˙ radical scavenging activity (log(koverall) = 4.6–5.1) at pH < 5; however, at pH = 5.4–8.8, the highest HOO˙ radical scavenging activity were observed for 3 with log(koverall) = 5.2–5.7. At pH > 6.2, acids 2, 3, 4, and 5 presented the largest radical scavenging activity. By contrast, acid 3-coumaric acid (8) had the lowest antiradical activity at most pH values. Thus, the hydroperoxyl radical scavenging activity in pentyl ethanoate follows the order 3 > 5 > 1 ∼ 2 ∼ 4 ∼ 6 (homovanillic acid) ∼ 7 > 8, whereas it follows the order 3 > 2 ∼ 4 ∼ 5 > 6 ∼ 7 > 1 > 8 in water at pH = 7.40. The activity of 1, 2, 3, 4, 5, 6, and 7 are faster than those of the reference Trolox, suggesting that these HCA could be useful natural antioxidants in the aqueous physiological environment.

Autonomous self-optimizing defects by refining energy levels through hydrogenation in CeO2–x polymorphism: a walking mobility of oxygen vacancy with enhanced adsorption capabilities and photocatalytic stability

The proposed work on ceria photocatalyst shows facile reactivity of oxygen anions with hydrogen molecules, turning inefficient highly disordered CeO2−x into optimized disordered H-CeO2−x which sustains optimized oxygen vacancies and Ce3+ defects.

Synthesis of well-defined linear-bottlebrush-linear triblock copolymer towards architecturally-tunable soft materials.

Linear–bottlebrush–linear (LBBL) triblock copolymers are emerging systems for topologically-tunable elastic materials. In this paper, a new synthetic methodology is presented to synthesize LBBL polystyrene-block-bottlebrushpolydimethylsiloxane-block-polystyrene (PS-b-bbPDMS-b-PS) triblock copolymer via the “grafting onto” approach where the precursors are individually synthesized through living anionic polymerization and selective coupling reaction. In this two-step approach, polystyrene-block-polymethylvinylsiloxane (PS-b-PMVS) diblock copolymer with a low dispersity couples with another living PS block to form PS-b-PMVS-b-PS triblock copolymer. Secondly, this is followed by grafting of separately prepared monohydride-terminated PDMS chains with controllable grafting density through a hydrosilylation reaction. In addition to fully tunable architectural parameters, this approach permits a quantitative determination of the ratio of diblock and triblock bottlebrush copolymers and consistency between batches, highlighting the feasibility for scaled-up production. These LBBL triblock copolymers self-assemble into soft, low-modulus thermoplastic elastomers, and the precise knowledge of the composition is crucial for correlating microstructure to mechanical properties.

Dynamic ionic behavior of gel-free diolefin rubber-based carboxylate ionomers preparedviaolefin metathesis

Constructing dynamic ionic bonding interactions is acknowledged as an efficient strategy to improve the physical-mechanical characteristics of rubber materials, and to provide them with some novel features such as self-healing. However, currently reported grafting-modification approaches such as free-radical and anionic reactions inevitably induced the generation of rubber gels, which is unfavorable for their practical applications. In this work, we fabricated a gel-free carbonylated diolefin rubber based on the olefin metathesis reaction. Furthermore, a diolefin rubber-based ionomer was prepared through the complexation of carbonylated diolefin rubber and sodium hydroxide. Compared with pure diolefin rubber, the resultant ionomers exhibited a higher glass transition temperature (Tg), higher mechanical strength and higher damping properties. Moreover, these ionomers were provided with apparent self-healing behavior. This was primarily because of the increased dynamic ionic bonding interactions induced by the formation of multi-ion-pair cluster structures, a unique intermolecular interaction that exists in the ionomers. Consequently, the gel-free diolefin rubber-based ionomers offer some brand-new applications, such as artificial skin and high-performance "green" tires.

8π Electrocyclic Reaction of Phosphonate Derivatives: Access to Seven-Membered Cross-Conjugated Cyclic Trienes.

An anionic 8π electrocyclic reaction of 4-(diethoxyphosphoryl)-1,3,6-heptatriene derivatives was developed. Under the influence of a base, the substrate underwent deprotonation at the C5 position followed by the 8π electrocyclization of the resulting heptatrienyl anion. The subsequent Horner-Wadsworth-Emmons reaction in one pot, following the addition of an aldehyde, resulted in the production of the 3-alkylidene-1,4-cycloheptadiene derivative. The electrocyclic reaction proceeded in a stereospecific manner, resulting in the stereocontrolled formation of two neighboring stereogenic centers.

Ligation of Boratabenzene and 9-Borataphenanthrene to Coinage Metals.

The reactions of boratabenzene and borataphenanthrene anions with group 11 Ph3PMCl reagents furnished η2 coordination complexes, with the exception of the copper boratabenzene species that adopted an η6 mode. The binding of arene ligands to copper in an η6 manner is rare, and altering the ancillary ligand on copper to an N-heterocyclic carbene switched the binding of the boratabenzene to η2, indicating that such ligands are capable of vacating coordination sites. The η2 coordination complexes bind side-on, akin to olefins, via a borataalkene unit, although with the carbon atom much more proximal to the metal center than boron.

Unraveling vacancy-induced oxygen redox reaction and structural stability in Na-based layered oxides

The promising P2-layered sodium manganese oxide (Na2/3MnO2) cathode often suffers from multiple structural transformations due to the Jahn–Teller distortion induced by Mn3+, hence the rapid capacity falloff. Other than many previous studies on partial substitution of Mn by low valence ions, here we have introduced vacancies into Mn sites in P2-Na2/3MnO2 (e.g., Na2/3[□1/6Mn5/6]O2, where □=vacancy) to oxidize Mn close to Mn4+. Combined experimental and theoretical studies reveal that such vacancy introduction overcomes the detrimental structural distortion due to irreversible phase transitions to O2 and OP4 and triggers oxygen redox activated by an orphaned O 2p state around Mn vacancies in addition to the conventional cationic redox. P2-Na2/3[□1/6Mn5/6]O2 shows smooth and continuous charge/discharge curves indicative of restrained phase transitions, leading to much superior cycling stability than the Jahn-Teller distorted pristine counterpart. This study demonstrates the critical role of transition-metal vacancies in triggering the anionic redox reaction and manipulating the phase transitions in P2-type layered cathodes.

Integrated Study of the Thiocyanate Anion Electrooxidation by Electroanalytical and Computational Methods

The mechanism of the electrochemical oxidation of thiocyanate anion in acetonitrile was studied by cyclic voltammetry, chronoamperometry, electrolysis, digital simulations and quantum chemical calculations. The experimental data indicated complex character of the reaction mechanism, which includes reactions of thiocyanate anion with the products of its oxidation, thiocyanate radical and thiocyanogen. It was proposed that the last reaction takes place in the reduction of thiocyanogen as well. The DFT PCM-SMD M06–2X/aug-CC-pVQZ calculations show that the reaction of thiocyanate anion with thiocyanate radical and disproportionation of thiocyanogen anion radical are thermodynamically favorable. The effects of the mentioned reactions on the shape of the curves of cyclic voltammetry and chronoamperometry as well as that of the mass transfer regime are discussed.

SET activation of nitroarenes by 2-azaallyl anions as a straightforward access to 2,5-dihydro-1,2,4-oxadiazoles

The use of nitroarenes as amino sources in synthesis is challenging. Herein is reported an unusual, straightforward, and transition metal-free method for the net [3 + 2]-cycloaddition reaction of 2-azaallyl anions with nitroarenes. The products of this reaction are diverse 2,5-dihydro-1,2,4-oxadiazoles (>40 examples, up to 95% yield). This method does not require an external reductant to reduce nitroarenes, nor does it employ nitrosoarenes, which are often used in N–O cycloadditions. Instead, it is proposed that the 2-azaallyl anions, which behave as super electron donors (SEDs), deliver an electron to the nitroarene to generate a nitroarene radical anion. A downstream 2-azaallyl radical coupling with a newly formed nitrosoarene is followed by ring closure to afford the observed products. This proposed reaction pathway is supported by computational studies and experimental evidence. Overall, this method uses readily available materials, is green, and exhibits a broad scope.

Surface oxygen vacancy engineering and physical protection by in-situ carbon coating process of lithium rich layered oxide

Lithium-rich layered oxide (LLO) with a large specific capacity (>250 mAhg −1 ) and the wider voltage window (2.0–4.8 V) delivers an energy density of about 1000 Wh/kg. However, oxygen release from the surface of LLO and decomposition of electrolyte solvents leads to increased electrode-electrolyte interface resistance. To achieve the maximum energy density of LLO, it becomes mandatory to protect the surface structure and simultaneously activate the cationic and anionic redox reaction. Here, we demonstrate a novel in-situ carbon encapsulation on Li 1.15 Ni 0.23 Co 0.08 Mn 0.54 O 2 by the industrially viable co-precipitation process followed by solid-state reaction. Effect of carbon encapsulation on structure formation, chemical composition, and elemental oxidation states of Li 1.15 Ni 0.23 Co 0.08 Mn 0.54 O 2 are analyzed by the techniques such as X-ray diffraction, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. The enhanced electrochemical performance is confirmed by increased coulombic efficiency, reduced interfacial resistance, and suppressed voltage fading. Moreover, carbon-coated LLO retains an excellent capacity of 94% after 300 cycles at 2C rate cycling, while the pristine LLO retained only 77.8% of capacity. Further, electrochemical cycling of carbon encapsulated LLO with pre-lithiated graphite delivers an energy density of 500 Wh/kg after 100 cycles at 0.5C rate (150 mAg −1 ). • In-situ Carbon coating on Li1.15Ni0.23Co0.08Mn0.54O2. • Surface oxygen vacancy engineering. • Electrochemical cycling of Li1.15Ni0.23Co0.08Mn0.54O2with pre-lithiated graphite. • Surface protection from carbon coating.