Preparation and evaluation of α-Al2O3 supported lithium ion sieve membranes for Li+ extraction

Spinel lithium manganese oxide ion-sieves have been considered the most promising adsorbents to extract Li⁺ from brines and sea water. Here, we report a lithium ion-sieve which was successfully loaded onto tubular α-Al₂O₃ ceramic substrates by dipping crystallization and post-calcination method. The lithium manganese oxide Li₄Mn₅O₁₂ was first synthesized onto tubular α-Al₂O₃ ceramic substrates as the ion-sieve precursor (i.e. L-AA), and the corresponding lithium ion-sieve (i.e. H-AA) was obtained after acid pickling. The chemical and morphological properties of the ion-sieve were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Both L-AA and H-AA showed characteristic peaks of α-Al₂O₃ and cubic phase Li₄Mn₅O₁₂, and the peaks representing cubic phase could still exist after pickling. The lithium manganese oxide Li₄Mn₅O₁₂ could be uniformly loaded not only on the surface of α-Al₂O₃ substrates but also inside the pores. Moreover, we found that the equilibrium adsorption capacity of H-AA was 22.9 mg·g⁻¹. After 12 h adsorption, the adsorption balance was reached. After 5 cycles of adsorption, the adsorption capacity of H-AA was 60.88% of the initial adsorption capacity. The process of H-AA adsorption for Li⁺ correlated with pseudo-second order kinetic model and Langmuir model. Adsorption thermodynamic parameters regarding enthalpy (∆ H), Gibbs free energy (∆ G) and entropy (∆ S) were calculated. For the dynamic adsorption–desorption process of H-AA, the H-AA exhibited excellent adsorption performance to Li⁺ with the Li⁺ dynamic adsorption capacity of 9.74 mg·g⁻¹ and the Mn²⁺ dissolution loss rate of 0.99%. After 3 dynamic adsorption–desorption cycles, 80% of the initial dynamic adsorption capacity was still kept.     

Li1.6Mn1.6O4/PVDF多孔膜的制备及提锂性能

自制锂离子筛前驱体Li_1.6Mn_1.6O₄，并将Li_1.6Mn_1.6O₄粒子与高分子树脂PVDF杂化制膜，研究了膜经稀盐酸抽锂后对锂的吸附性能以及多次吸附与脱附性能等。结果表明，膜M-10-55[Li]采用0.5 mol·L^-1 HCl溶液抽锂约2 h锂的脱出基本达到平衡，Li⁺的洗脱率在95%左右，锰的溶损率为3.5%左右。抽锂后得M-10-55[H]对富锂溶液中锂的吸附约12 h达平衡，对锂的吸附容量较高为41 mg·g^-1，在第5次吸附时对锂的提取量为35 mg·g^-1左右。相比于Na⁺、K⁺、Mg²⁺、Ca²⁺，该膜对Li⁺表现出较好的选择性，对于从海水、盐湖卤水等液态锂资源中提取锂有很大的开发潜力。     

Effect of sol composition on solid electrode/solid electrolyte interface for all-solid-state lithium ion battery

A property of interface between solid electrode and solid electrolyte is one of the most important keys to fabricate all-solid-state lithium ion battery. In this study, an influence of sol composition used for preparation of the electrode on the property of interface between electrode and electrolyte was examined. LiMn₂O₄/honeycomb Li_0.55La_0.35TiO₃ (LLT) and Li₄Mn₅O₁₂/honeycomb LLT half cells were fabricated by impregnation of mixture of active materials with various precursor sols into honeycomb holes. In the case of LiMn₂O₄ cathode, the sol composed of nitrate salt provides large contact area of LiMn₂O₄ and LLT, resulting in higher performance of the cell. Li₂MnO₃ impurity was produced at Li₄Mn₅O₁₂/LLT interface prepared by the precursor sol composed of only nitrate or acetate salts although no impurity phase was observed at the interface prepared by acetate–nitrate sol containing lithium acetate and manganese nitrate. Li₄Mn₅O₁₂/honeycomb LLT half cell prepared by the acetate–nitrate sol showed the best performance among them. It is concluded that composition of the precursor sol strongly influenced on the interface of electrode and electrolyte. The all-solid-state Li ion battery composed of LiMn₂O₄/honeycomb LLT/Li₄Mn₅O₁₂ was successfully operated and the discharge capacity was 32 μAh cm⁻².     

Solvent Extraction of Li+ using Organophosphorus Ligands in the Presence of Ammonia

In this work, the selective extraction of Li⁺ with the aid of organophosphorus ligands (H-OP) including phenylphosphonic (H-PHO), phenylphosphinic (H-PHI) and bis(2-ethylhexyl) phosphoric (H-BIS) acids in the absence and presence of ammonia was studied. Adding NH₃ to the aqueous phase resulted in significant improvement in the % extraction of Li⁺ into the organic phase containing H-OP ligands. The highest % extraction values obtained in the case of H-PHO, H-PHI, and H-BIS were 43.2%, 45.7%, and 90.0%, respectively. Two mechanisms were inferred; the first was that the extraction equilibrium reaction of LiCl + H-OP ? Li-OP + HCl shifted forward due the reaction of the produced HCl with NH₃. The second mechanism was that the Li⁺/NH₄⁺ exchange of NH₄-OP (produced from the reaction of H-OP with NH₃) was easier than Li⁺/H⁺ exchange of H-OP itself. Competitive extraction experiments indicated that the selectivity factors of Li⁺ over Na⁺ and K⁺ were strongly dependent on the concentration of H-OP ligands which suggested that aggregation of ligand molecules via hydrogen bonding is the limiting factor for selectivity.     

Why is aluminum-based lithium adsorbent ineffective in Li+ extraction from sulfate-type brines

Aluminum-based lithium adsorbent (Li/Al-LDH) is the only industrialized adsorbent for Li⁺ extraction from salt lake brines. The inherent mechanism of declined Li⁺ adsorption performance was revealed to explain the feebleness in sulfate-type brines. SO₄²⁻ in brines could replace interlayer Cl⁻ by a stronger electrostatic attraction with laminates, significantly altering the stacking structure and interlayer spacing, while Cl K-edge of XAFS showed intercalated SO₄²⁻ would not obviously change the chemical environment of interlayer Cl⁻. Experiments as well as DFT and FEM simulations indicated the intercalated SO₄²⁻ regulated Li⁺ adsorption of Li/Al-LDHs at different ionic strength under a combined effect of expanded interlayers, close packing, and electrostatic repulsion. Although sufficient SO₄²⁻ contents in brines might promote the single Li⁺ adsorption by offering ionic strength as a driving force, the long-term usability would be severely impaired as SO₄²⁻ intercalation in interlayers reduced the subsequent Li⁺ adsorption capacity and increased the desorption difficulty.     

Spinel LiMn2O4 cathode materials for lithium storage: The regulation of exposed facets and surface coating

Minimal Mn dissolution was achieved with surface Mn⁴⁺-rich phase-modified truncated octahedral spinel LiMn₂O₄ with exposed {111} planes, which was synthesized via a simple hydrothermal reaction, followed by high temperature calcination in an oxygen atmosphere. The calcination atmosphere had a significant influence on the formation of the surface Mn⁴⁺-rich phase-modified layer; LiMn₂O₄ without a surface Mn⁴⁺-rich phase was obtained by calcination in an air atmosphere. Benefiting from the unique structure, the as-prepared LiMn₂O₄ exhibited an excellent rate capability and prolonged cycle stability, delivering a discharge capacity of 101 mAh g⁻¹ and capacity retention rates of about 94% and 88% after 500 and 1000 cycles at 1C, respectively, compared to a discharge capacity of 86 mAh g⁻¹ and a capacity retention rate of about 86% after 500 cycles at 1C for the LiMn₂O₄ prepared in an air atmosphere. The synergistic effect of the unique truncated octahedral morphology of spinel LiMn₂O₄ with {111} exposed planes and the modification of the surface Mn-rich phase endowed the composite with excellent electrochemical properties.     

Low temperature performance of copper/nickel modified LiMn2O4 spinels

This study presents an evaluation of structural changes resulting from cycling modified copper/nickel LiMn₂O₄ spinels at 263 K. In situ synchrotron XRD shows that cycling LiMn₂O₄ at 263 K resulted in the formation of mixed cubic and tetragonal phases with a consequent lower capacity. The differential capacitance profile normally exhibiting two peaks at 298 K is modified, showing only one oxidation peak at 263 K in the 4 V region. The changes observed are attributed to interactions between Jahn-Teller active Mn³⁺ species and Li⁺ ions. These changes are not observed once copper/nickel modified spinels are being evaluated, because of the decrease in Mn³⁺ population. All the observed changes are fully reversible once the material is cycled back at 298 K.     

Origin of the high voltage (>4.5 V) capacity of spinel lithium manganese oxides

With an objective to develop a better understanding of the origin of high voltage (>4.5 V) capacities, the electrochemical behaviors of a number of spinel lithium manganese oxides with and without other transition metal ions have been studied and compared. The oxides investigated are LiMn_2−yM_yO₄ (M=Co, Ni, and Cu), LiMn_2−y−zM_yLi_zO₄, LiMn_2−yLi_yO₄, Li₂Mn₄O_9−δ, and Li₄Mn₅O₁₂. The LiMn_2−yLi_yO₄ (0.05≤y≤0.12) oxides are found to exhibit capacity above 4.5 V although they do not contain other transition metal ions. In the case of Li₂Mn₄O_9−δ and Li₄Mn₅O₁₂, charging above 4.5 V is found to increase the discharge capacity below 4.5 V. While both LiMn_2−yCo_yO₄ and LiMn_2−y−zCo_yLi_zO₄ show a similar behavior at >4.5 V, LiMn_2−yNi_yO₄ and LiMn_2−y−zNi_yLi_zO₄ differ significantly. Also, while LiMn_1.9Li_0.1O₄ and LiMn_1.8Co_0.2O₄ show a rapid decrease in their discharge capacity above 4.5 V with rest time allowed in the fully charged state (self-discharge), LiMn_2−yNi_yO₄ does not suffer from such a difficulty. Additionally, long-range periodicity with good crystallinity is found to be essential to observe discharge capacity above 4.5 V. The results are explained on the basis of the participation of the O²⁻:2p band in the redox process and the relative positions of the other transition metal ion redox energies with respect to the top of the O²⁻:2p band.     

Rational design of electrochemically active polymorphic MnOx/rGO composites for Li+-rechargeable battery electrodes

Electrochemical behavior of different MnO_x @reduced graphene oxide (rGO) composites derived from a MnO₂/GO template are thoroughly investigated. As-prepared MnO₂/GO mixture is gradually converted to MnO₂/rGO and finally to Mn₃O₄/rGO composites under controlled post annealing conditions. The semispherical Mn₃O₄ crystalline compound anchored composite exhibits stable electrode performances, including both the Li⁺ anode and the Li⁺-air cathode catalyst, induced by the electrochemically favorable composite with an effective large contact area between the active materials and the electronic conductive rGO. It is such a meaningful to suggest the facile and controllable synthetic procedures for obtaining Li-rechargeable electrodes with a MnO_x nanoparticle-incorporated composites for the highly reactive lithiation/delithiation electrochemical reactions.     

Extraction relationship of Li+ and H+ using tributyl phosphate in the presence of Fe(III)

ABSTRACT

During the extraction of lithium from high Mg-containing salt lake brines by tributyl phosphate (TBP) in the presence of Fe(III), H⁺ is used to stabilize Fe(III). However, the distribution ratio of H⁺ (D_H) is 4–6 times higher than that of Li⁺ (D_Li), which affects the extraction of Li⁺ significantly. In this study, the competition mechanism between H⁺ and Li⁺ was investigated by spectral analysis and thermodynamic equilibrium. The extracted species are determined as HFeCl₄ · 2TBP and LiFeCl₄ · 2TBP for H⁺ and Li⁺, respectively. The apparent equilibrium constants are K_H = 799.8 and K_Li = 120.6, respectively. Both equilibrium constants and the distribution ratios for H⁺ and Li⁺ extraction show that extraction of H⁺ is stronger than Li⁺.     

Investigation of lithium ion kinetics through LiMn2O4 electrode in aqueous Li2SO4 electrolyte

Spinel LiMn₂O₄ was prepared by sol–gel method and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscope. Cyclic voltammogram, galvanostatic charge/discharge testing, and electrochemical impedance spectroscopy (EIS) techniques were employed to evaluate the electrochemical behaviors of LiMn₂O₄ in 1 M Li₂SO₄ aqueous solution. Two redox couples at E _SCE = 0.78/0.73 and 0.91/0.85 V were observed, corresponding to those found at E _Li/Li ⁺= 4.05/3.95 and 4.06/4.18 V in organic electrolyte. The discharge capacity of pristine LiMn₂O₄ in aqueous electrolyte was 57.57 mAh g⁻¹, and the capacity retention of the electrode is 53.7 % after 60 cycles. Only one semicircle emerged in EIS at different potentials in aqueous electrolyte, while three semicircles were observed in organic electrolytes. There was no solid electrolyte interface film on the surface of spinel LiMn₂O₄ electrode in aqueous electrolyte. The change of kinetic parameters of lithium ion insertion in spinel LiMn₂O₄ with potential in aqueous electrolyte for initial charge process was discussed in detail, and a suitable model was proposed to explain the impedance response of the insertion materials of lithium ion batteries in different electrolytes.     

All-solid-state lithium battery with a three-dimensionally ordered Li1.5Al0.5Ti1.5(PO4)3 electrode

To fabricate all-solid-state Li batteries using three-dimensionally ordered macroporous Li_1.5Al_0.5Ti_1.5(PO₄)₃ (3DOM LATP) electrodes, the compatibilities of two anode materials (Li₄Mn₅O₁₂ and Li₄Ti₅O₁₂) with a LATP solid electrolyte were tested. Pure Li₄Ti₅O₁₂ with high crystallinity was not obtained because of the formation of a TiO₂ impurity phase. Li₄Mn₅O₁₂ with high crystallinity was produced without an impurity phase, suggesting that Li₄Mn₅O₁₂ is a better anode material for the LATP system. A Li₄Mn₅O₁₂/3DOM LATP composite anode was fabricated by the colloidal crystal templating method and a sol-gel process. Reversible Li insertion into the fabricated Li₄Mn₅O₁₂/3DOM LATP anode was observed, and its discharge capacity was measured to be 27 mA h g⁻¹. An all-solid-state battery composed of LiMn₂O₄/3DOM LATP cathode, Li₄Mn₅O₁₂/3DOM LATP anode, and a polymer electrolyte was fabricated and shown to operate successfully. It had a potential plateau that corresponds to the potential difference expected from the intrinsic redox potentials of LiMn₂O₄ and Li₄Mn₅O₁₂. The discharge capacity of the all-solid-state battery was 480 μA h cm⁻².     

Mn4+ activated dodec-fluoride red phosphor Na3Li3In2F12:Mn4+ with excellent waterproof stability for WLEDs

Mn⁴⁺ activated fluoride red phosphors, as candidate red materials in white light-emitting diodes (WLEDs), have received widespread attention. However, the poor water stability limits their application. Herein, a novel dodec-fluoride red phosphor Na₃Li₃In₂F₁₂:Mn⁴⁺ with good waterproof stability was successfully synthesized by solvothermal method. The crystal structure, optical property, micro-morphology, element composition, waterproof property and thermal behavior of Na₃Li₃In₂F₁₂:Mn⁴⁺ phosphor were analyzed. Under the 468 nm blue light excitation, the Na₃Li₃In₂F₁₂:Mn⁴⁺ phosphor has narrow emission bands in the area of 590–680 nm. Compared with commercial red phosphor K₂SiF₆:Mn⁴⁺, the Na₃Li₃In₂F₁₂:Mn⁴⁺ phosphor possesses better waterproof stability. When soaked in water for 360 min, the PL intensity of the Na₃Li₃In₂F₁₂:Mn⁴⁺ phosphor remains at initial 80%. Finally, warm WLEDs with CRI of 87 and CCT of 3386 K have been fabricated using blue InGaN chip, YAG:Ce³⁺ yellow phosphor and Na₃Li₃In₂F₁₂:Mn⁴⁺ red phosphor.     

Adsorption behavior of Li+ onto nano-lithium ion sieve from hybrid magnesium/lithium manganese oxide

Magnesium (II) doped spinel lithium manganese oxide (LMS) was synthesized by soft chemical method and nanosized ion sieve manganese oxide (HMS) was prepared by extracting lithium and magnesium from LMS. The characteristics of HMS were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, surface areas and determination of pH at the point of zero charge. Experiments were performed to study the effects of pH, adsorbent dose, contact time and Li⁺ concentration. The competitive model was used to describe the competition between Li⁺–H⁺ and the applicability of different kinetic models was evaluated. The results showed that the pH at the point of zero charge of HMS was about 7.8. The recycle of HMS explained that it could be used as Li⁺ adsorbent with topotactical extraction of lithium. Under optimized batch conditions up to 99.2% Li⁺ could be recovered from solution within 24 h. The adsorption process followed the pseudo-second-order model and followed an intraparticle diffusion model at the beginning.     

Optimization of Lithium Content and Sintering Aid for Maximized Li+ Conductivity and Density in Ta‐Doped Li7La3Zr2O12

Ta‐doped cubic phase Li₇La₃Zr₂O₁₂ (LLZ) lithium garnet received considerable attention in recent times as prospective electrolyte for all‐solid‐state lithium battery. Although the conductivity has been improved by stabilizing the cubic phase with the Ta⁵⁺ doping for Zr⁴⁺ in LLZ, the density of the pellet was found to be relatively poor with large amount of pores. In addition to the high Li⁺ conductivity, density is also an essential parameter for the successful application of LLZ as solid electrolyte membrane in all‐solid‐state lithium battery. Systematic investigations carried out through this work indicated that the optimal Li concentration of 6.4 (i.e., Li_6.4La₃Zr_1.4Ta_0.6O₁₂) is required to obtain phase pure, relatively dense and high Li⁺ conductive cubic phase in Li_7?xLa₃Zr_2?xTa_xO₁₂ solid solutions. Effort has been also made in this work to enhance the density and Li⁺ conductivity of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ further through the Li₄SiO₄ addition. A maximized room‐temperature (33°C) total (bulk + grain boundary) Li⁺ conductivity of 3.7 × 10^?4 S/cm and maximized relative density of 94% was observed for Li_6.4La₃Zr_1.4Ta_0.6O₁₂ added with 1 wt% of Li₄SiO₄.     

An efficient far-red emission Sr2InSbO6:Mn4+, M (M = Li+, Na+, and K+) phosphors for plant cultivation LEDs

High-efficiency and far-red light phosphors based on Mn⁴⁺-doped inorganic luminescence materials are beneficial to plant cultivation. However, Mn⁴⁺-doped oxide phosphors have a common problem of low quantum efficiency. Alkali metal ion codoping can effectively improve the luminescence properties of Mn⁴⁺-activated oxide phosphors. Herein, a series of Sr₂InSbO₆:Mn⁴⁺, M (SISO:Mn⁴⁺, M) (M = Li⁺, Na⁺, and K⁺) far-red-emitting phosphors codoped alkali metal ions were first synthesized. Density functional theory calculation indicated that SISO is a kind of indirect bandgap material with a bandgap of ∼1.60 eV. The SISO:Mn⁴⁺ samples showed a far-red light at 698 nm upon 365 nm, which perfectly matched the absorption spectrum of the far-red-phytochrome (Pfr) of plants. The doping concentration of the SISO:Mn⁴⁺ samples was optimized to be 0.006 mol. The concentration quenching mechanism was defined as dipole–dipole interaction by combining the Dexter theory and the Inokuti–Hirayama model. Optimizing the sintering temperature and codoped with alkali metal ions (Li⁺, Na⁺, and K⁺) could improve the luminescent intensity of SISO:Mn⁴⁺. The optimum sintering temperature was 1300°C. The internal quantum efficiencies of SISO:0.006Mn⁴⁺ and SISO:0.006Mn⁴⁺, 0.006Li⁺ phosphors are 22.67% and 60.56%, respectively. SISO:Mn⁴⁺, Li⁺ phosphors-based plant growth light-emitting diodes (LEDs) demonstrate excellent optical stability and long lifetime. Thus, these phosphors are promising candidates for plant cultivation LEDs.     

Local charge regulation by doping Li+ in BaGa2O4:Bi3+ to generate multimode luminescence for advanced optical Morse code

In the field of advanced anti-counterfeiting research, it is a hot issue to develop a multimodal anti-counterfeiting material with adjustable luminescence characteristics. Here, persistent luminescent materials of BaGa₂O₄:xBi³⁺ (x = 0-0.02) and BaGa₂O₄:0.005Bi³⁺,yLi⁺ (y = 0.001–0.02) were synthesized by a solid state reaction at high temperature. BaGa₂O₄: Bi³⁺ exhibited a broad blue emission at ～470 nm (transition from [GaO₄]) and a sharp NIR emission at ～710 nm (³P₁→¹S₀ transition of Bi³⁺), upon UV excitation at 250 nm. Incorporation of Li⁺ in BGO: 0.005Bi³⁺ induced the emission color shifting from blue to green. After stoppage of UV excitation, the BGO:0.005Bi³⁺ exhibited white afterglow with emission peaks at the range of 500–700 nm. However, incorporation of Li⁺ leaded to a stronger green afterglow and a weaker NIR afterglow. When the afterglow disappeared, the sample outputted afterglow again after heating processing. The prepared samples exhibited time- and temperature-dependent multimode luminescence, so they were used as components, combined with Morse code to realize multi-modal dynamic anti-counterfeiting. The outcomes in this work indicate that the prepared luminescent materials have broad prospects in advanced anti-counterfeit applications.     

High energy storage density achieved in Bi3+-Li+ co-doped SrTi0.99Mn0.01O3 thin film via ionic pair doping-engineering

The demand for lead-free dielectric capacitors with rapid charge-discharge ability and high energy storage density is increasing owing to the rapid development of electronic equipment. Lead-free Sr_1-x(Bi_0.5Li_0.5)_xTi_0.99Mn_0.01O₃ (x = 0.02, 0.025, 0.03, 0.035) thin films grown on Pt/Ti/SiO₂/Si substrates were prepared by sol-gel method. A huge enhancement in polarization was found in Bi³⁺-Li⁺ co-doped SrTiO₃ thin films. The large lattice distortion and local broken-symmetry due to formation of Bi³⁺-Li⁺ ionic pairs are responsible for ferroelectricity and high polarization. The maximum polarization (42.1 μC/cm²) and largest energy storage density of 47.7 J/cm³ at 3307 kV/cm were both achieved in Sr_0.975(Bi_0.5Li_0.5)_0.025Ti_0.99Mn_0.01O₃ thin film. Moreover, an excellent temperature-dependent stability was also obtained in Sr_0.975(Bi_0.5Li_0.5)_0.025Ti_0.99Mn_0.01O₃ thin film from 30 to 110 °C.     

Structural and electrochemical characteristics of Li0.7[Li1/6Mn5/6]O2 synthesized using sol-gel method

Layered O₂-lithium manganese oxide (O₂-Li_0.7[Li_1/6Mn_5/6]O₂) was prepared by ion-exchange of P2-sodium manganese oxide (P2-Na_0.7[Li_1/6Mn_5/6]O₂)· P2-Na_0.7[Li_1/6Mn_5/6]O₂ precursor was first synthesized by using a sol-gel method, and then O₂-Li_0.7[Li_1/6Mn_5/6]O₂ was produced by an ion exchange of Li for Na in the P2-Na_0.7[Li_1/6Mn_5/6]O₂ precursor. Structural and electrochemical analyses suggested that good quality O2-Li_0.7[Li_1/6Mn_5/6]O₂ was prepared from P2-Na_0.7[Li_1/6Mn_5/6]O₂ synthesized at 800 °C for 10 h using glycolic acid as a chelating agent. During the cycle, the discharge profile of the synthesized samples showed two plateaus at around 4 and 3 V, respectively, with a steep slope between the two plateaus. The discharge curve at 3 V escalated with an increase in the cycle number, presenting a phase transition from a layered to a spinel like structure. The sample prepared at 800 ‡C for 10 h using glycolic acid delivered a discharge capacity of 187 mAh/g with small capacity fading.     

The role of co-dopants on the luminescent properties of α-Al2O3:Mn4+ and BaMgAl10O17:Mn4+

Mn⁴⁺ doped aluminate materials with efficient red emission are promising components for warmer white light-emitting diodes. However, it still remains as a challenge on increasing its luminous efficiency. For Mn⁴⁺ doped aluminate phosphors, co-dopants such as Li⁺, Mg²⁺, Na⁺, Si⁴⁺, or Ge⁴⁺ ions are often added to tailor the photoluminescence properties of phosphors during preparing process. However, the role of the ions is still in debate. In this work we took BaMgAl₁₀O₁₇:Mn (BMA:Mn) and α-Al₂O₃:Mn as examples to study the effects of Li⁺, Mg²⁺, Na⁺, and Si⁴⁺ on their luminescent properties. The energy levels induced by the co-dopants and some possible intrinsic defects of hosts (Al₂O₃) were calculated using the first-principles method. It is found that the Mg²⁺ and Na⁺ ions, compared with Li⁺ and Si⁴⁺, can prefer to form hole-type defects which enhance the valence stability of Mn⁴⁺ and thus enhance the emission intensity of the as-prepared phosphors.