Amount Of Doping Research Articles

Tailoring BaCe0.7Zr0.1(Dy0.1|Yb0.1)0.2O3−δ electrolyte through strategic Cu doping for low temperature proton conducting fuel cells: Envisioned theoretically and experimentally

This study addresses the challenge of high sintering temperatures in proton-conducting fuel cells (PCFCs) with BaCeO3-doped electrolytes. We demonstrate that 1 mol% copper (Cu) doping at the B-site of BaCe0.7Zr0.1(Dy0.1|Yb0.1)0.2O3−δ (BCZDYb) improves sintering behavior, enabling densification at 1400 °C. However, Cu doping disrupts stoichiometry, creating barium vacancies and reducing proton-accepting cations, affecting overall conductivity. This mechanism is confirmed through density functional theory (DFT) calculations and various experimental techniques, including crystal structure analysis using X-ray diffraction (XRD) and morphology and elemental analysis via field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS). Electrochemical measurements are performed using the electrochemical impedance spectroscopy (EIS). The ionic conductivity of 1 mol% Cu-doped BCZDYb (BCZDYb-1) is 1.49×10−2 S cm−1 at 650 °C, which is 3.8 times higher than that of BCZDYb sintered at 1200 °C. The BCZDYb-1 exhibits ∼3.5 times higher conductivity when sintered at 1200 °C and ∼16 times higher grain boundary conductivity when sintered at 1400 °C, compared to undoped BCZDYb. The single cell employing BCZDYb-1 as the electrolyte achieved a power density of ∼606 mW cm−2 at 550 °C. These results indicate that a controlled amount of Cu doping can enhance densification while maintaining high ionic conductivity, making it suitable for practical applications in PCFCs operating at lower temperatures.

Nickel doped enhanced LaFeO3 catalytic cracking of tar for hydrogen production

The transformation of biomass into green energy was pivotal for sustainable development, yet the efficient conversion of biomass-derived tar into hydrogen-rich syngas remained a significant challenge. This study addressed the catalytic demand for hydrogen production from tar, focusing on the development of LaNixFe1-xO3 perovskites as catalysts. A series of LaNixFe1-xO3 perovskites with varying nickel doping levels (x=0, 0.25, 0.5, 0.75, 1) were synthesized to evaluate their catalytic performance in converting toluene, a representative tar component, into hydrogen. The LaNi0.5Fe0.5O3 catalyst demonstrated the highest hydrogen yield (14.5L/6h) and volume percentage (82.9V/V%), highlighting the optimal nickel doping level for enhancing hydrogen production. The hydrogen production performance of LaNixFe1-xO3 was significantly affected by nickel doping. In particular, a small amount of nickel doping can significantly enhance the hydrogen production capacity of LaFeO3 and maintain good reaction stability. The enhanced performance was attributed to the high oxygen storage capacity of perovskite, which facilitated the removal of surface carbon and promotes the methanation reaction. Notably, the total content of defect oxygen and surface adsorbed oxygen/hydroxyl groups significantly impacted the hydrogen production efficiency. These findings indicated that LaNi0.5Fe0.5O3 was an effective catalyst for converting biomass-derived tar into hydrogen-rich syngas, offering a promising solution to the catalytic demand in the hydrogen production system.

ZnSnO3 micro-polyhedrons with oxygen defects derived from rubidium incorporation for enhanced ethanol detection

Detecting ethanol in ambient air is of great significance in protection of ecological environment, human health and social economy. Herein, a strategy is adopted to substantially improve the gas sensing performance of the ZnSnO3 micro-polyhedrons through rubidium (Rb) doping. In this study, a series of ZnSnO3 micro-polyhedrons with different amounts of Rb doping were successfully synthesized through a typical hydrothermal procedure and air sintering. The sensor based on 2 mol% Rb-doped ZnSnO3 exhibits high response value (108) and rapid response/recover speed (20/8 s) to 100 ppm ethanol at 260 °C, as well as outstanding repeatability and stability. Combining theoretical calculations and various characterization techniques, the improved sensing property of the 2 mol% Rb-doped ZnSnO3 to ethanol gas can be ascribed to the large specific surface area and the abundant surface defects induced by Rb incorporation. We believe that this study opens up a new perspective for developing efficient and high-performance ethanol gas sensor.

Effect of structure of metal-free nitrogen-doped coal-based carbon on catalytic oxygen reduction

In carbon-based oxygen reduction reaction (ORR) catalysts, metal-free nitrogen-doped carbon-based materials generally have higher catalytic stability compared to metal catalysts with reduced catalytic activity due to the occurrence of metal agglomeration during the catalytic reaction. In this paper, a metal-free nitrogen-doped carbon-based ORR catalyst NCOH5-900 with a half-wave potential of 0.846 V and onset potential of 0.94 V was prepared using coal as the carbon source, dicyandiamide as the nitrogen source and KOH as the activator. The material has good ORR catalytic performance with half-wave potential and onset potential comparable to Pt/C catalyst with the same mass loading, with better resistance to methanol toxicity and catalytic stability. The physical and chemical properties of the prepared catalyst were controlled by adjusting the amount of nitrogen doping and activation temperature to establish the relationship between the material structure and the ORR performance. The results suggest that for the metal-free nitrogen-doped carbon-based material, the good ORR catalytic performance is attributed to the abundant edge defects, high graphitization, good mixed structure of micro/mesopores, large nitrogen content, and high ratio of pyridine to graphitic nitrogen. Finally, the catalytic mechanism of NCOH5-900 for ORR is investigated using in-situ attenuated total reflection Fourier infrared (ATR-FTIR) and in-situ Raman, confirming the four-electron reduction process of O2 via a continuous dual step of two-electron transfer process.

Effect of increasing alkali layer spacing on the performance of O3-NaNi1/3Fe1/3Mn1/3O2 cathode materials

O3-Na1-xCax/2Ni1/3Fe1/3Mn1/3O2 (NaCNFMx, x=0, 0.05, 0.1, 0.15) was prepared by doping calcium ions and replacing the sodium sites in the NaNi1/3Fe1/3Mn1/3O2 (NaNFM) material using ball milling spray. XRD, SEM and XPS results demonstrated that the calcium element was successfully embedded in the lattice. The electrochemical performance of NaCNFM0.1 is the best when the doping amount of calcium ion is 0.1. The sodium diffusion coefficient of NaCNFM0.1 cathode material after 3 cycles is 1.67×10-14 cm2/s. The first specific discharge capacity at 1C is 121.1mAh/g. Even at the high current density of 5C, the 200cycles capacity of 103.6mAh/g is much higher than NaNFM's 95.2mAh/g, and the capacity retention rate is as high as 91.5%. Ex-situ XRD and SEM analyses manifested that the moderate amount of calcium doping improved the stability of the layered structure. These results show that the cathode material has great application potential.

Simultaneous structure and surface engineering of metal-organic framework derived LiNi0.5-xFe2xMn1.5-xO4 cathode material for improving high voltage performance of lithium-ion batteries

This study presents a novel material synthesis approach utilizing a terephthalic acid-based metal-organic framework as a precursor and employing an ethanol-assisted hydrothermal treatment to produce high-performance Fe-doped LiNi0.5Mn1.5O4 (LNMO) cathode material. This strategy yields a well-crystallized spinel structure with uniformly distributed transition metal ions. Additionally, the appropriate quantity of Fe dopant can achieve the desired Mn3+/Mn4+ ratio, level of structural disordering, and crystal phase purity for Fe-doped LNMO. The synthesis process also aids in forming an amorphous Li2CO3 surface layer, approximately 1 nm thick, which protects the active material from excessive reaction with electrolyte. The typical Fe-doped LNMO cathode (S-05) exhibits superior performance compared to a commercialized LNMO counterpart. It delivers an initial discharge capacity of 135 mAh g-1 at 1 C with exceptional cycling stability over 500 cycles (capacity retention of 90%) under high voltage (5.0 V vs. Li+/Li). Furthermore, its rate capability significantly improves, with a capacity retention of 85% (5 C/0.2 C). This enhanced performance aligns with evidence of activated Ni2+/Ni3+/Ni4+ redox reactions and suppressed cathode electrolyte interphase resistance, leading to promoted Li+ diffusion. Moreover, it is found the cathode helps alleviate electrolyte degradation at high voltages by inhibiting the formation of singlet oxygen in the electrolyte.

Investigating the influence mechanism of aluminum doping amount on the density and grain size of AZO target through phase-field simulation

This study proposes a three-phase model (primary, secondary, and pore phases) utilizing the phase-field method to simulate sintering densification in AZO targets. The impact of secondary phase content and dimensions on the densification of AZO targets was investigated. The findings indicated that the density of the AZO target exhibited an initial increase followed by a subsequent decline with the augmentation of the secondary phase content and size. Conversely, the grain size demonstrated a continuous reduction. The Brook kinetic equation yields activation energies for grain growth of 607.40kJ/mol, 999.32kJ/mol, and 1093.20kJ/mol for 1wt%, 2wt%, and 3wt% Al2O3, respectively. Furthermore, the viability of the model was corroborated through experimentation. Based on the simulation outcomes, AZO targets doped with 2wt% Al₂O₃ achieved 99.78% densification, an average grain size of 3.92 μm, and a resistivity of 1.38 mΩ·cm.

Study on capacity of HPSB hydrogen storage material catalyzed by Sm2O3

HPSB (Hydrolysis Product of Sodium Borohydride) hydrogen storage material is a kind of porous lamellar structural material developed by our research group. Due to the special structure of this material, it can absorb hydrogen at room temperature, hydrogen absorption pressure is 2–4 MPa, and hydrogen absorption time is 2–5 min. The main preparation method used in the experiment is hydrolysis. The main raw material is sodium borohydride, and the reaction temperature is 30 °C. In this experiment, in order to improve the hydrogen storage performance of HPSB hydrogen storage material, Co–B and Sm2O3 were introduced as catalysts during the preparation of HPSB. The results show that the amount of Sm2O3 and the ratio of Sm2O3 to Co–B have obvious influence on the hydrogen storage performance of HPSB. In addition, according to the results of SEM analysis, the amount of Sm2O3 and the ratio of Sm2O3 to Co–B also have obvious effects on the microstructure of HPSB hydrogen storage materials. The sample with a doping amount of 4 wt% and a ratio of Sm2O3 to Co–B of 4:6 can release 2.17 wt% H2.

Effect of vanadium doping on electrochemical properties of lithium iron manganese phosphate

Abstract The low-cost lithium iron manganese phosphate anode material has a 15% higher energy density than lithium iron phosphate, and it has received wide attention in recent years. However, the poor electronic/ionic conductivity of lithium ferromanganese phosphate leads to poor power performance, which makes it difficult to meet the needs of practical applications. In this study, a V-doped LiMn0.2Fe0.8PO4(LFMP) material is designed and prepared, and every particle is coated by a uniform carbon layer. The V-doped LFMP material shows better rate performance and cycle performance. When the optimal vanadium doping amount is 0.01, the specific discharge capacity of the material is 164.0 mAh/g at 0.1 C.

A novel strategy for obtaining lead-based piezoelectric ceramics with giant piezoelectricity and high-temperature stability through the construction of “slush-like” polar states

Maintaining high piezoelectric response and piezoelectric temperature stability of lead-based piezoceramics is critical for applications under high-temperature environments. Unfortunately, the piezoelectric response of lead-based piezoceramics shows strong temperature dependence. Herein, an innovative strategy was proposed to solve this problem. The method consisted of constructing “slush-like” polar states by introducing localized heterostructures in the tetragonal phase structure to lower the energy barriers. The presence of the tetragonal phase stabilized the domain structure, providing excellent temperature stability, while the localized heterostructures also flattened the free energy landscape and enhanced the piezoelectric response. The strategy was implemented by using 0.11Pb(In0.5Nb0.5)O3-0.89Pb(Hf0.47Ti0.53)O3(PIN-PHT) piezoceramics doped with heterovalent ion Nb5+ to form a “slush-like” polar state with strong interactions inside the ceramics. The piezoelectric response and relaxor behavior of the ceramics were then investigated using piezoelectric force microscopy to reveal the mapping relationship between the complex ferroelectric domain structure and both the piezoelectric response and temperature stability. At Nb5+ doping amount of 0.8 mol%, the ceramics showed excellent comprehensive performances with d33 = 764 pC/N, Tc = 319.1 °C, εr = 3253.59, kp = 0.67, and tanδ = 0.0122. At an external ambient temperature of 300°C, the d33 of PIN-PHT-0.8Nb5+ remained high at 734 pC/N, with piezoelectric performance retention of 96.1%, showing excellent temperature stability. Overall, a new path was proposed for developing Pb-based piezoceramics with both good piezoelectric response and high-temperature stability, promising to broaden the temperature range of high-temperature piezoceramics for various applications.

Preparation and mechanical properties of Al-doped TiC films

Abstract Al-doped TiAlxC films were prepared on different substrates (single crystal Al2O3 (0001), stainless steel, and silicon wafer substrates) by co-sputtering, and microstructures and corresponding mechanical properties of TiAlxC films were tested and analyzed. The results indicate that the microhardness of the prepared TiAlxC films would decrease with the increased doping amount of Al while the corresponding friction coefficient would increase. With the increase of Al doping, the excess Al hinders the growth of the nanocrystalline phase in the TiAlxC film, thereby affecting the hardness and wear resistance of the TiAlxC film. When the Al doping is 4.1 at%, the hardness of the film reaches 2, 890 HV, while the friction coefficient is 0.2, indicating that a small amount of Al plays a role in solution strengthening the film. Therefore, the mechanical properties of the Al-doped TiAlxC films could be tailored by the doping amount of Al.

Synthesis and Electrochemical Performance Enhancement of Li2MnSiO4 Cathode Material for Lithium‐Ion Batteries via Mn‐Site Ni Doping

AbstractIn exploring the potential of Li2MnSiO4 as a cathode material for lithium‐ion batteries (LIBs), the key challenges often involve enhancing electronic conductivity and lithium‐ion diffusion rates. To address these issues, this paper proposes the combination of solid‐state doping and a two‐step calcination process to successfully prepare the Li2Mn1−xNixSiO4 series of cathode materials, where Ni substitutes Mn at different doping amounts (x = 0, 0.02, 0.04, 0.06, 0.08). The use of chemically equivalent Ni2+ ions to replace Mn2+ ions is an effective method. Since the ionic radius of Ni2+ is smaller than that of Mn2+, this substitution can create more voids in the lattice structure. These increased voids provide smoother channels for the transport of electrons and lithium ions, thereby improving the material's electrical conductivity. At a Ni doping amount of 0.06, the material exhibits optimal electrochemical performance, achieving a discharge capacity of 155 mAh g−1 at 0.1 C, significantly superior to undoped lithium manganese silicate. The doping of Mn sites with Ni significantly improves the conductivity and lithium‐ion diffusion capabilities of Li2MnSiO4, revealing the tremendous potential of doping strategies in optimizing the performance of LIBs cathode materials.

Post-growth annealing effect of Li-doped NiO thin films grown by mist chemical vapor deposition

Nickel oxide (NiO) thin films were grown by mist chemical vapor deposition (mist CVD) with various amounts of Li dopant in the precursor (0–15 %). As the Li dopant readily decomposed under the high temperature above 700℃, the post-growth annealing was conducted at 600–800 °C. The crystal quality of the undoped and Li-doped NiO films was improved by thermal annealing due to the crystal reconstruction. The optical transmittance of NiO films was decreased with increasing the amounts of Li dopants, whereas it was increased with thermal annealing. The bandgap of the NiO films was slightly red-shifted with increased amounts of Li dopants, whereas it was blue-shifted with increasing annealing temperature. The resistivity of as-grown NiO films ranged from 25–75 Ω·cm with Li doping. Electrical properties abruptly decreased under a high annealing temperature of 700 °C. Hence, an appropriate combination of Li doping and post-growth annealing might improve the structural properties of the NiO thin films while retaining the p-type conductivity.

Flexural toughness and stress-strain relationship of different types of steel fiber reinforced shotcrete in high geothermal environment

The shape of steel fiber plays a pivotal role in determining the mechanical properties of concrete. In this paper, the impacts of end-hooked, wavy and ultra-fine steel fibers (all with a doping amount of 1.0 %) on the compressive strength, flexural strength, flexural toughness, and strain-strain relationship of shotcrete under curing conditions of 20 ℃, 40 ℃, and 60 ℃ are studied. Furthermore, the flexural toughness of steel fiber shotcrete is evaluated using the energy absorption method, and a constitutive model for steel fiber shotcrete was established based on meso-damage mechanics theory. The results indicate that curing temperatures below 40 ℃ are conducive to enhancing the compressive strength, flexural strength, and flexural toughness of steel fiber shotcrete, while curing temperatures above 60 ℃ are unfavorable for the development of strength and toughness in steel fiber shotcrete. Regardless of the type of steel fiber, its incorporation can alleviate the negative impact of high-temperature curing on the strength and toughness of shotcrete. Under high-temperature curing conditions, the influence of end-hooked steel fibers on the strength of shotcrete is superior to that of corrugated and ultrafine steel fibers, while ultrafine steel fibers are beneficial for improving the flexural toughness of shotcrete. The slope, peak stress, and peak strain of the stress-strain curves of shotcrete cured at 40 ℃ and 60 ℃ with the addition of the three types of steel fibers are greater than those of concrete without steel fibers. Furthermore, the descending segment of the curve is wider and smoother, with a larger surrounding area, demonstrating good toughness, deformability, and ductility. The end-hooked steel fibers and ultrafine steel fibers exhibit superior performance in enhancing the toughness and ductility of shotcrete under high-temperature curing conditions compared to wavy steel fibers. Based on meso-damage theory, the impacts of curing temperature and steel fiber types on the constitutive model of shotcrete under axial compression were established, and the model parameters were discussed. The research results can provide theoretical support for the durability design of tunnel linings in high ground temperature environments.

Research on electrical conductive properties of thulium-doped calcium zirconate solid electrolyte

To further investigate the electrochemical performance of Tm doped CaZrO3 electrolyte, the CaZr1−xTmxO3−α (x = 0, 0.025, 0.05, 0.075 and 0.1) solid electrolyte specimens were prepared by high temperature solid state method. The phase structure and microstructure of the electrolyte samples were analyzed by Raman spectrum, XRD and SEM. The electrical conductivity of the specimen was measured at the temperature of 673∼1373K in hydrogen-rich and oxygen-rich atmosphere by the two-terminal AC impedance spectroscopy method. The H/D isotope effect of the specimen at different temperature was tested to confirm the dominant conducting carrier in predetermined temperature and atmosphere. It is found that proton is the dominant charge carrier both in oxygen-rich and hydrogen-rich atmosphere at the lower temperature below 1073 K. However, at higher temperature above 1073K, the predominant charge carrier seems to be oxygen ion vacancy in hydrogen-rich, whereas to be electron hole in oxygen-rich atmosphere, based on the analysis of the atmospheric dependence of the electrical conductivity. Moreover, partial conductivities of conducting species, the active doping amount of Tm and the standard Gibbs free energy changes for interstitial proton production by dissolution of water and hydrogen in Tm doped electrolyte were estimated based on crystal defect chemistry theory.

Two birds with one stone: A ferrocene-based zirconium(IV)-organic framework nanosheet denoting intrinsic high proton conductivity and acting as a fine dopant to chitosan-based composite membranes

Recently, it was demonstrated that employing metal-organic frameworks (MOFs) with prominent proton conductivity (σ) as fillers with organic substrates such as chitosan (CS) or Nafion is an effective approach for preparing composite membranes (CMs) with outstanding functionalities. Inspired by this, one extremely stable Zr(IV)-MOF (namely Zr-FDC) with a nanosheet structure produced by 1,1′-ferrocene dicarboxylic acid (H2FDA) was successfully manufactured in this research and subsequently used as a filler to synthesize a series of CS-based CMs via casting method. The alternating current (AC) impedance determinations manifested that both Zr-FDC and the related CS-based CMs (CS/MOF-x; x = 2, 4, 6, 8 being the mass percentage of Zr-MOF in the CM) showed ultrahigh σ values, indicating the structural advantages of the Zr-MOF. Further research verified that when the MOF doping quantity is 4 %, the CM's (CS/MOF-4) σ is the greatest, being 2.22 × 10−2 S/cm, which is boosted by nearly tenfold at 100 °C and 98 % relative humidity (RH) compared to the original MOF (3.2 × 10−3 S/cm). Furthermore, the CM exhibits superior thermal stability and tensile resistance. Finally, considering the structural features of the MOF and CS, activation energy data, and other determinations, we thoroughly theorized the proton conduction process within the MOF framework and CMs, referencing the subsequent proton exchange membrane design.

Structural Transformation of Metastable Two-Electron Superatom Au-Doped Cu-Rich Alloy Nanocluster.

The ability to fabricate bimetallic clusters with atomic precision offers promising prospects for elucidating the correlations between their structures and properties. Nevertheless, achieving precise control at the atomic level in the production of clusters, including the quantity of dopant, characteristic of ligands, charge state of precursors, and structural transformation, have remained a challenge. Herein, we report the synthesis, purification, and characterization of a new bimetallic hydride cluster, [AuCu11(H){S2P(OiPr)2}6(C≡CPh)3] (AuCu11H). The hydride position in AuCu11H was determined using DFT calculations. AuCu11H comprises a ligand-stabilized defective fcc Au@Cu11 cuboctahedron. AuCu11H is metastable and undergoes a spontaneous transformation through ligand exchange into the isostructural [AuCu11(Cl){S2P(OiPr)2}6(C≡CPh)3] (AuCu11Cl) and into the complete cuboctahedral [AuCu12{S2P(OiPr)2}6(C≡CPh)4]+ (AuCu12) through an increase in nuclearity. These structural transformations were tracked by NMR and mass spectrometry.

Introduction of a Hydroxyl Self-Sacrificing Surface on Ultrathin Poly(heptazine imide) Nanosheets by KCl Grafting: A New Strategy to Improve the Photocatalytic Production of H2O2.

The generation of H2O2 through photocatalysis is increasingly recognized as a viable approach for addressing the energy and environmental challenges encountered in industrial production processes. In this research, we synthesized ultrathin (1 nm) poly(heptazine imide) (PHI) nanosheets as a photocatalyst by a one-step KCl molten salt process. The utilization of Fourier transform infrared and X-ray photoelectron spectroscopy substantiated that the interlayer-bonded potassium atoms induce polarization in water molecules, facilitating the attachment of hydroxyl groups on the surfaces of nanosheets. These groups serve as self-sacrificing entities, promoting the reaction that leads to the generation of H2O2. The preparation temperature and KCl doping amount factors for the H2O2 generation rate were investigated, and the mechanism of the KCl-bonded structure on photogeneration charge separation transport was analyzed. Owing to the elevated crystallization and the presence of surface self-sacrificing hydroxyl groups, the rate of H2O2 production reaches 6117.5 and 308.35 μmol·g-1·h-1 under visible-light irradiation (λ ≥ 420 nm) in isopropanol solution and pure water, respectively. These rates are 30 and 18.7 times higher than those observed for bulk g-C3N4, respectively. The photocatalytic kinetic processes for H2O2 formation and decomposition were also calculated to investigate the catalyst activities.

Enhancing the electrochemical performance of Ni-doped CuCo2O4 electrode material through 2D layered sheets

Abstract In the present study, the structural and electrochemical properties on Ni–CuCo2O4 (0 ≤ x ≤ 10 %) was studied for the use of active electrode materials in asymmetric supercapacitors prepared by a simple hydrothermal process. The synthesized material’s morphology shows that the nanosheets are assembled with an average diameter of about 50 nm, and the X-ray diffraction results show the spinel cubic structure with the space group of Fd-3mz (No. 227). CuCo2O4 electrodes exhibit a high specific capacitance for the electrodes because of the abundant redox reactions of Co2+/Co3+ and Co3+/Co4+, and Ni at the Co site has displayed exceptional charge-discharge and cyclic stability properties. The electrochemical studies show that the Ni doped CuCo2O4 electrode has the highest pseudocapacitive nature, with ultra-specific capacitances of 803 F g−1, 889 F g−1, 924 F g−1, and 1,086 F g−1 at 1 A g−1 respectively for pure, 2, 6, and 10 % Ni doped CuCo2O4 electrodes. Further, the excellent rate capability with 82 % capacitance retention and 92.3 % Coulombic efficiency were realized after 1,000 cycles. Moreover, the M-H study at room temperature showed paramagnetic behaviour. Additionally, the electrochemical and magnetic characteristics of the CuCo2O4 system is expected to improve as the doping quantity of Ni increased. This study may pave the way for enhanced properties of Ni doped CuCo2O4 for futuristic hybrid devices applications.

In-situ formation of spinel protective layer through extremely low K-doping for enhanced performance of Ni-rich layered cathodes

Herein, we demonstrate a novel and feasible strategy to stabilize the LiNi0.83Co0.12Mn0.05O2 (NCM) structure via the in-situ formation of a superficial spinel layer with potassium (K) doping. While K+ doped NCM is not new, the formation of the protective spinel layer gives surprising results with even a trace amount of doping, which is unique and novel, and nowhere reported. The structural transformation from layered to spinel on the surface region of NCM is achieved with a K-doping level of 0.05 mol% (NCM-0.05K) and the formed spinel layer acted as a protective pillar for stabilizing the host structure, leading to substantially improved electrochemical performance. The X-ray photoelectron spectra demonstrate a large increase in nickel (Ni2+) distribution after cycling for pristine but almost no change for the NCM-0.05K, suggesting a stable preformed spinel layer. The above results reveal that the K+ doping can strongly reduce the Ni4+ to stable Ni2+ under the spinel phase formation and improves cell performances in terms of specific capacity, capacity retention, rate capability, and Li+ diffusivity. The internal micro-cracking of host NCM is also effectively suppressed by the low amount of K doping. Excessive K-doping, in contrast, leads to a reduction in (de)lithiation rate and greater polarization.