Substitution Of Al For Mn Research Articles

(Invited, Digital Presentation) Pushing the Limits of High Nickel NMC Cathodes

Lithium-ion batteries now dominate electrochemical energy storage for vehicle propulsion and grid storage in addition to portable electronics. In 2022, they celebrate their 50th anniversary, and yet still achieve only 25% of their theoretical energy density. The dominant anode and cathode today are graphitic carbon and the layered NMC oxides, LI[NiMnCoAl]O2. Both need improving. Most of the carbon in the anode must go, and the NMCs need pushing to their limit and at the same time eliminating cobalt. I will today discuss the challenges faced as we push the limits of the NMCs to their limits, > 80% lithium cycling, and Ni>0.8 and Co <<0.1. The higher the Ni content the lower the charging voltage needed for a given cycling capacity, but the greater its surface and bulk reactivity. The issues discussed will include 1stcycle loss [1], high rate capability [2], cathode stability [3], and surface/bulk reactivity and the impact of surface/bulk modification [4,5] and the micron-size single crystals vs meatballs on these [6]. This work is being supported by DOE-EERE-BMR-Battery500 consortium.[1]. Hui Zhou, Fengxia Xin, Ben Pei, M. Stanley Whittingham, “What Limits the Capacity of Layered Oxide Cathodes in Lithium Batteries?”, ACS Energy Lett. 2019, 4: 1902−1906.[2]. Chunmei Ban, Zheng Li, Zhuangchun Wu, Melanie J. Kirkham, Le Chen, Yoon Seok Jung, E. Andrew Payzant, Yanfa Yan, M. Stanley Whittingham, and Anne C. Dillon “Extremely Durable High-Rate Capability of a LiNi0.4Mn0.4Co0.2O2 Cathode Enabled by Single–Wall Carbon Nanotubes”, Advanced Energy Materials, 2011, 1: 58-62.[3]. Hyung-Joo Noh, Sungjune Youn, Chong Seung Yoon, Yang-Kook Sun “Comparison of the structural and electrochemical properties of layered Li[NixCoyMnz]O2 (x = ¼ 1/3, 0.5, 0.6, 0.7, 0.8 and 0.85) cathode material for lithium-ion batteries”, J. Power Sources, 2013, 233: 121-130.[4]. Fengxia Xin, Hui Zhou, Yanxu Zong, Mateusz Zuba, Yan Chen, Natasha A. Chernova, Jianming Bai, Ben Pei, Anshika Goel, Jatinkumar Rana, Feng Wang, Ke An, Louis F. J. Piper, Guangwen Zhou, and M. Stanley Whittingham, “What is the Role of Nb in Nickel-Rich Layered Oxide Cathodes for Lithium-Ion Batteries?”, ACS Energy Letters, 2021, 6: 1377-1382.[5]. Ben Pei, Hui Zhou, Anshika Goel, Mateusz Zuba, Hao Liu, Fengxia Xin, and M. Stanley Whittingham, “Al Substitution for Mn during Co-Precipitation Boosts the Electrochemical Performance of LiNi0.8Mn0.1Co0.1O2”, J. Electrochemical Society, 2021, 68: 050532.[6]. Yujing Bi, Jinhui Tao, Yuqin Wu, Linze Li, Yaobin Xu, Enyuan Hu, Bingbin Wu, Jiangtao Hu, Chongmin Wang, JiGuang Zhang, Yue Qi and Jie Xiao, “Reversible planar gliding and microcracking in a single-crystalline Ni-rich cathode”, Science, 2020, 370: 1313-1317.

Al Substitution for Mn during Co-Precipitation Boosts the Electrochemical Performance of LiNi0.8Mn0.1Co0.1O2

Nickel-rich layered oxides, such as LiNi0.8Mn0.1Co0.1O2 (NMC 811), are considered as one of the most promising candidates for the next-generation cathode because of their high energy densities and relatively low cost. However, the poor first Coulombic efficiency of NMC 811 leads to around a 15% capacity loss in the first cycle at a cut-off voltage of 4.4 V. Moreover, the structure degradation during cycling results in capacity fading and safety concerns, due to potential oxygen loss after charging. Here, with aluminum substitution for manganese through a developed continuous co-precipitation approach, the electrochemical performance of NMC 811 cathodes has been greatly enhanced. Among different Al% substituted samples, LiNi0.8Mn0.06Co0.1Al0.04O2 cathodes reduced by 50% the first capacity loss of pristine NMC 811(18.0 vs 35.9 mAh g−1) and improved the capacity retention from 81.4 to 96.4% after 60 cycles at 0.5C in the voltage range of 2.8–4.4 V.

Different Effects of Al Substitution for Mn or Fe on the Structure and Electrochemical Properties of Na0.67Mn0.5Fe0.5O2 as a Sodium Ion Battery Cathode Material.

P2-type layered oxides based on the elements Fe and Mn have attracted great interest as sodium ion battery (SIB) cathode materials owing to their inexpensive metal constituents and high specific capacity. However, they suffer from rapid capacity fading and complicated phase transformations. In this study, we modulate the crystal structure and optimize the electrochemical performances of Na0.67Mn0.5Fe0.5O2 by Al doping for Mn or Fe, respectively, and the roles of Al in the enhancement of the rate capability and cycling performance are unraveled. (1) The substitution of Al for Mn or Fe decreases the lattice parameters a and c but enlarges d spacing and lengthens Na-O bonds, which enhances Na+ diffusion and rate capability especially for Na0.67Mn0.5Fe0.47Al0.03O2. (2) Al doping reduces the thickness of TMO2 and strengthens TM-O/O-O bonding. This enhances the layered structure stability and the capacity retention. (3) Al doping mitigates Mn3+ and Jahn-Teller distortion, mitigating the irreversible phase transition. (4) Al doping also alleviates the lattice volume variation and the structure strain. This further improves the stability of the layered structure and the cycling performances particularly in the case of Al doping for Fe. The in-depth insights into the roles of Al substitution might be also useful for designing high-performance cathode materials for SIBs through appropriate lattice doping.

Magnetostructural phase transitions and magnetocaloric effects in as-cast Mn1-xAlxCoGe compounds

Abstract The structural and magnetic properties of as-cast Mn 1-x Al x CoGe (0 ≤ x ≤ 0.05) have been studied by X-ray diffraction, differential scanning calorimetry, and magnetization measurements. The partial substitution of Al for Mn in Mn 1-x Al x CoGe results in a decrease in the martensitic transition temperature T M . For the concentration range 0 ≤ x ≤ 0.01, T M was found to coincide with ferromagnetic transition temperature (T C ) resulting in a first-order magnetostructural transition (MST). A further increase in aluminum concentration resulted in a splitting of the phase transition temperatures, which included a drastic decrease in the martensitic temperature. The compounds with x > 0.02 showed a single transition at T C . The maximum values of the magnetic entropy changes (-ΔS M ) were ∼18 J/kgK, 12 J/kgK, and 7 J/kgK for ΔH = 5T at 313 K (x = 0.00), 286 K (x = 0.01), and 220 K (x = 0.02), respectively. The maximum value of the relative cooling power (RCP) was found to be 303 J/kg for x = 0.01 at T = 286 K for ΔH = 5T. It has been established that as-cast samples of this system show large value of MCE near room temperature making this system a promising material for magnetic cooling technologies.

Effects of the substitution of Al for Mn on structure, magnetic, and magnetocaloric properties in MnCoGe

The magnetic transition can be controlled by partial substitution of Al for Mn in Mn1−xAlxCoGe, leading to a wide transition temperature range around the room temperature. A well-defined linear relationship between the magnetic entropy change (|ΔSM|) and H2/3 demonstrates the second-order character of magnetic transition. In the case of x = 0.02, the relative cooling power of 242.3 J·kg−1 is achieved for Δμ0H = 5 T at 270.5 K. Interestingly, a corresponding monotonical decline in |ΔSM| is in relation to magnetic moment per formula unit. The observed large relative cooling power with wide phase transition temperatures makes these materials promising for room-temperature magnetic cooling applications.

Tuning the Mn valence state in new Ca(0.66)Mn(2-x)Al(x)O4 (x≤ 0.4) oxides: impact on magnetic and redox properties.

New Ca(0.66)Mn(2-x)Al(x)O4 (x≤ 0.4) solid solutions crystallizing with the CaFe2O4-type structure (SG: Pnma) were synthesized for the first time by the glycine-nitrate process. The structures were determined on the basis of XRD Rietveld analysis and electron diffraction investigation. While the CaMn3O6 ('Ca(0.66)Mn2O4') oxide adopts a monoclinic unit cell, the Al substitution for Mn (x = 0.2, 0.4) leads to an orthorhombic cell with only two Mn atomic positions, with different valence states, and 33% of Ca sites empty. The Ca molar concentration decreases down to 0.6 in order to increase the Mn valence leading to a phase mixture, whereas a slight Ca content increase up to 0.7 leads to a decrease of Mn valence in the pure phase. The Al(3+) ions are located at a specific Mn site because their ionic radii are close to that of Mn(4+) and a more isotropic environment. The unit cell parameters and volume strongly decrease for a low Al content and tend to an asymptotic value of x = 0.33-0.4, around the limit of solubility. As the Al content increases, the Mn valence state in the same slightly distorted octahedral site increases up to 4+ whereas the other octahedral site is highly elongated and corresponds mainly to Jahn-Teller Mn(3+). At x = 0.33, these two Mn sites correspond to Mn(4+) and Mn(3+) respectively. Moreover, the aluminium content increase induces a weakening of the global antiferromagnetic long range interactions between the ferromagnetic chains. The Al substitution leads to the change of the Mn valence distribution as well as the unit cell symmetry of the CaMn3O6 phase. These 1D tunnel networks stabilizing the Mn(3+)/Mn(4+) valence states can be reduced under Ar/5%H2 between T = 300 °C and T = 600 °C (heating rate = 2 °C min(-1)) into pure Mn(2+) rocksalt solid solution despite the large difference in ionic radii. The re-oxidation leads to the same CaFe2O4-type structure and several redox cycles can be operated. The relationship between the two double chains of the edge-sharing octahedral sites and the rocksalt-type framework is clear and should appear as the driving force for the structural transformation during the reduction/oxidation processes. Finally, Al substitution allows an increasing of the Mn-O bond covalence and consequently the reduction in temperature.

Martensitic phase transformations and magnetocaloric effect in Al co-sputtered Ni–Mn–Sb alloy thin films

Abstract We systematically investigated the influence of aluminium (Al) content on the martensitic transformations and magnetocaloric effect (MCE) in Ni–Mn–Sb ferromagnetic shape memory alloy (FSMA) thin films. The temperature-dependent magnetization (M–T) and resistance (R–T) results displayed a monotonic increase in martensitic transformation temperature (TM) with increasing Al content. From the isothermal magnetization (M–H) curves, a large magnetic entropy change (ΔSM) of 23 mJ/cm3 K was observed in N49.8Mn32.97Al4.43Sb12.8. A remarkable enhancement of MCE could be attributed to the significant change in the magnetization of Ni–Mn–Sb films with increasing Al content. Furthermore, a high refrigerant capacity (RC) was observed in Ni–Mn–Sb–Al thin films as compared to pure Ni–Mn–Sb. The substitution of Al for Mn in Ni–Mn–Sb thin films with field induced MCE are potential candidates for micro length scale magnetic refrigeration applications where low magnetic fields are desirable.

Mitigation of layer to spinel conversion of a lithium-rich layered oxide cathode by substitution of Al in a lithium ion battery

The layer to spinel structure conversion of lithium-rich layered oxides during cycling could be alleviated by equal substitution of Al for Mn and Ni, resulting in better capacity retention and average voltage.

Magnetic properties of LiNi0.5Mn0.47Al0.03O2 as positive electrode for Li-ion batteries

The layered LiNi0.5Mn0.47Al0.03O2 was synthesized by wet chemical method and characterized by X-ray diffraction and analysis of magnetic measurements. The powders adopted the α-NaFeO2 structure. This substitution of Al for Mn promotes the formation of Li(Ni0.472+Ni0.033+Mn0.474+Al0.033+)O2 structures and induces an increase in the average oxidation state of Ni, thereby leading to the shrinkage of the lattice unit cell. The concentration of antisite defects in which Ni2+ occupies the (3a) Li lattice sites in the Wyckoff notation has been estimated from the ferromagnetic Ni2+(3a)–Mn4+(3b) pairing observed below 140 K. The substitution of 3% Al for Mn reduces the amount of antisite defects from 7% to 6.4–6.5%. The analysis of the magnetic properties in the paramagnetic phase in the framework of the Curie–Weiss law agrees well with the combination of Ni2+ (S = 1), Ni3+ (S = 1/2) and Mn4+ (S = 3/2) spin-only values. Delithiation has been made by the use of K2S2O8. According to this process, known to be softer than the electrochemical one, the nickel ions in the (3b) sites are converted into Ni4+ in the high spin configuration, while Ni2+(3a)–Mn4+(3b) ferromagnetic pairs remain, as the Li+(3b) ions linked to the Ni2+(3a) ions in the antisite defects are not removed. The results show that the antisite defect is surrounded by Mn4+ ions, implying the nonuniform distribution of the cations in agreement with previous NMR and neutron experiments.

Pressure Dependent Magnetism in Y1.05(Mn0.95Al0.05)2

The Laves phase compound YMn2 exhibits a discontinuous transition from a spin fluctuating Pauli paramagnetic state above 110 K to an expanded, localised moment helical antiferromagnetic state below 110 K. Substitution of Al for Mn in the pseudo-binary compound Y(Mn1-xAlx)2 exerts a negative chemical pressure, expanding the unit cell and further localizing the Mn moment. Here we present the results of a μSR study of spin fluctuations in Y(Mn1-xAlx)2 (x = 0.05) in which external mechanical pressure (4.5 kbar) is applied to counteract the Al induced chemical pressure and destabilize the local Mn moment.

Structural and electrochemical properties of LiNi 0.5Mn 0.5 − xAl xO 2 ( x = 0, 0.02, 0.05, 0.08, and 0.1) cathode materials for lithium-ion batteries

Layered LiNi 0.5Mn 0.5 − x Al x O 2 ( x = 0, 0.02, 0.05, 0.08, and 0.1) series cathode materials for lithium-ion batteries were synthesized by a combination technique of co-precipitation and solid-state reaction, and the structural, morphological, and electrochemical properties were examined by XRD, FT-IR, XPS, SEM, CV, EIS, and charge–discharge tests. It is proven that the aliovalent substitution of Al for Mn promoted the formation of LiNi 0.5Mn 0.5 − x Al x O 2 structures and induced an increase in the average oxidation number of Ni, thereby leading to the shrinkage of the lattice volume. Among the LiNi 0.5Mn 0.5 − x Al x O 2 materials, the material with x = 0.05 shows the best cyclability and rate ability, with discharge capacities of 219, 169, 155, and 129 mAh g − 1 at 10, 100, 200, and 400 mA g − 1 current density respectively. Cycled under 40 mA g − 1 in 2.8–4.6 V, LiNi 0. 5Mn 0.45Al 0.05O 2 shows the highest discharge capacity of about 199 mAh g − 1 for the first cycle, and 179 mAh g − 1 after 40 cycles, with a capacity retention of 90%. EIS analyses of the electrode materials at pristine state and state after first charge to 4.6 V indicate that the observed higher current rate capability of LiNi 0. 5Mn 0.45Al 0.05O 2 can be understood due to the better charge transfer kinetics.

Room-temperature magnetocaloric effect in La0.7Sr0.3Mn1−xMx′O3 (M′=Al,Ti)

Magnetic entropy and adiabatic temperature changes in and above the room-temperature region have been measured for La0.7Sr0.3Mn1−xMx′O3 (M′=Al,Ti) by means of magnetization and heat capacity measurements in magnetic fields up to 6 T. The magnetocaloric effect becomes largest at the ferromagnetic ordering temperature Tc that is tuned (from 364.5 K for x=0) to ∼300 K by the substitution of Al or Ti for Mn. While the substitution of Al for Mn drastically reduces the maximum magnetic entropy (−ΔSm) and adiabatic temperature (ΔTa) changes, it extends considerably the working temperature span and therefore improves the relative cooling power (RCP). Under a magnetic field change ΔH=2 T, −ΔSm (or ΔTa) of La0.7Sr0.3Mn1−xAlxO3 decreases from 2.66 J/kg K (or 1.65 K) for x=0 to 1.18 J/kg K (or 0.69 K) for x=0.1, while RCP increases from 80.3 to 108.8 J/kg, respectively. While Tc is largely suppressed, the magnetocaloric effect is only lightly affected by the Ti substitution. With ΔH=2 T, the La0.7Sr0.3Mn0.95Ti0.05O3 sample exhibits −ΔSm (or ΔTa) =2.44 J/kg K (or 1.38 K) with RCP=89.9 J/kg. The decrease of magnetic moment is found to be one possible reason behind the suppression of the MCE. The magnetocaloric effect in manganite materials seems to be inhibited by the existence of short-range ferromagnetic correlations above Tc.

Room‐temperature magnetic entropy change in La0.7Sr0.3Mn1‐xMxO3 (M = Al, Ti)

AbstractMagnetic entropy change in and above the room‐temperature region has been measured for La0.7Sr0.3Mn1‐x Mx O3 (M = Al, Ti) by means of magnetization measurements in magnetic fields up to 6 T. The magnetocaloric effect (MCE) becomes strongest at the Curie temperature Tc that is tuned to ∼300 K by the substitution of Al or Ti for Mn. While the substitution of Al for Mn drastically reduces the entropy change, it extends considerably the working temperature span and improves the relative cooling power (RCP). The MCE and RCP seem to be only lightly affected by Ti substitution. Although manganites are considered potential for magnetic refrigerants, the limitations for achieving strong MCE in the materials are also discussed. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Structure and magnetic properties of TbMn6−xAlxSn6 compounds

In the present work, the influence of the substitution of Al for Mn on the structure and magnetic properties of TbMn6−xAlxSn6 compounds was investigated. With increasing Al concentration the lattice constants a, c, and the unit-cell volume V decrease monotonically. The TbMn6−xAlxSn6 compounds exhibit ferrimagnetic ordering. The magnetic ordering temperature first decreases with increasing Al content up to x=1.5, then increases with further increasing Al content. As for the unsubstituted material, it was found that this series of compounds exhibits a second magnetic transition at lower temperature that is attributed to spin reorientation. The spin-reorientation temperature and the magnetic anisotropy field first decrease with increasing Al content, go through a minimum at x=0.5, then increase with further increasing Al content. The saturation magnetization decreases monotonically with increasing Al content. Two metamagnetic transitions are found in TbMn6Sn6 compounds, one at 0.44 T, and the other at about 0.16 T. With increasing Al content only one metamagnetic transition remains.

The study on the hydrogen storage properties of MmNi 3.55Co 0.75Mn 0.7− xAl x compounds

In this work, the electrochemical properties of MmNi 3.55Co 0.75Mn 0.7− x Al x ( x = 0, 0.1, 0.2, 0.3, 0.4) compounds for secondary battery application were studied. We found that Al substitution for Mn can lower the hydride formation pressure and reduce the hysteresis between the hydrogen absorption and desorption pressure. The substitution of a small quantity of Al for Mn increases the hydrogen storage capacity of the compound. However, the slope of the plateau region and the discharge electrode potential increase and the hydrogen storage capacity decreases with further increases in Al content. According to our experimental results, the best alloy composition in this system is MmNi 3.55Co 0.75Mn 0.6Al 0.1.

Effect of aluminium for manganese substitution upon the GMR properties of the praseodymium manganites

The substitution of Al for Mn in the GMR perovskites Pr0.7Ca 0.2Sr0.1MnO3, Pr0.7Ca0.1Sr0.2MnO3 and Pr0.5Sr 0.5MnO3 has been studied. For the first two series of compounds that belong to the type I GMR manganites [ferromagnetic (FM)–paramagnetic (PM) transition]Tc decreases significantly as the aluminium content increases, by about 12 K per percent of Al atoms introduced into the Mn sites, whereas the maximum magnetoresistance ratio R0/HH is not modified dramatically, reaching 103 at 71 K for 6% Al per Mn in a magnetic field of 7 T. This increase of R0/RH is, in fact, correlated to the decrease of TC, i.e. to the increase of the semiconductive character of the samples. For the series Pr0.5Sr0.5Mn1 –xAlxO3, which belongs to type II [antiferromagnetic (AFM)-FM-PM transitions], an increase of TN from the AFM to the FM state is observed by Al doping: TN increases from 136 K for x= 0 to 170 K for x= 0.06. In contrast, Tc decreases as x increases.

Magnetic ordering and frustration in itinerant systems: RMn 2

The magnetism of RMn 2 and their pseudo-binary systems are reviewed in stressing the role of frustration for magnetic ordering. Mn moments in RMn 2 with the C15 structure are highly frustrated by themselves. Y(Sc)Mn 2 is paramagnetic even at the lowest temperature and has giant quantum spin fluctuations with antiferromagnetic correlation. Substituting Al for Mn, the system transfers to a spin-glass state. This behavior is explained by impurity effects on the frustrated system. Complicated magnetic structures and the partial existence of non-magnetic Mn atoms in DyMn 2, HoMn 2, Tb(Sc)Mn 2 are understood in terms of competing interactions incorporated with the instability of the Mn moment. The collapse of the ferromagnetic component GdMn 2, TbMn 2 by substitution of Al for Mn is discussed in terms of a random impurity effect.

Spin Liquid Behavior of Highly Frustrated Y(Sc)Mn2and Effects of Nonmagnetic Impurity

The roles of geometrical spin frustration in magnetic and thermodynamic properties of YMn 2 and Y(Sc)Mn 2 are studied. It is shown that the ground state of Y(Sc)Mn 2 , which exhibits heavy fermion like behavior, may be regarded as a quantum spin liquid realized through the frustration. To confirm this idea, magnetic, thermal and electrical properties of the Y 0.95 Sc 0.05 (Mn 1- x Al x ) 2 pseudobinary system have been studied. The substitution of Al for Mn causes a spin liquid to spin glass transition as a result of partial raise of spin configurational degeneracy.

ROLE OF FRUSTRATION IN MAGNETISM AND THERMODYNAMIC PROPERTIES OF YMn2 AND β-Mn

The temperature dependence of the magnetic susceptibility, the specific heat and the electrical resistivity of Y(Sc) (Mn1−xAlx)2 and β-Mn1−xAlx systems has been measured. It is shown that the ground state for x=0 is not a simple Pauli paramagnet but may be regarded as a quantum spin liquid. The substitution of Al for Mn results in the spin glass freezing. The role of frustration is discussed for understanding these phenomena.

Characteristic spin fluctuations in Y(Mn1-xAlx)2

The thermal expansion and magnetic susceptibility have been measured for Y(Mn1-xAlx)2 pseudobinary Laves phase intermetallic compounds. A large volume change at TN and a remarkable enhancement of the thermal expansion coefficient above TN were observed in YMn2. The substitution of Al for Mn makes these anomalies less clear. The temperature dependence of the susceptibility, being almost temperature independent for YMn2, becomes of the Curie-Weiss type as the Al content increases. Such behaviour is explained as the characteristic features of spin fluctuations. The amplitude of local spin fluctuations at the Mn site has been estimated on the basis of the phenomenological theory of magnetovolume effects. It has been revealed that the magnetic ground state of Al-substituted compounds is a spin glass.