Alkali Metal Ions Research Articles

Solution-based self-assembly synthesis of two-dimensional-ordered mesoporous conducting polymer nanosheets with versatile properties.

Conducting polymers with conjugated backbones have been widely used in electrochemical energy storage, catalysts, gas sensors and biomedical devices. In particular, two-dimensional (2D) mesoporous conducting polymers combine the advantages of mesoporous structure and 2D nanosheet morphology with the inherent properties of conducting polymers, thus exhibiting improved electrochemical performance. Despite the use of bottom-up self-assembly approaches for the fabrication of a variety of mesoporous materials over the past decades, the synchronous control of the dimensionalities and mesoporous architectures for conducting polymer nanomaterials remains a challenge. Here, we detail a simple, general and robust route for the preparation of a series of 2D mesoporous conducting polymer nanosheets with adjustable pore size (5-20 nm) and thickness (13-45 nm) and controllable morphology and composition via solution-based self-assembly. The synthesis conditions and preparation procedures are detailed to ensure the reproducibility of the experiments. We describe the fabrication of over ten high-quality 2D-ordered mesoporous conducting polymers and sandwich-structured hybrids, with tunable thickness, porosity and large specific surface area, which can serve as potential candidates for high-performance electrode materials used in supercapacitors and alkali metal ion batteries, and so on. The preparation time of the 2D-ordered mesoporous conducting polymer is usually no more than 12 h. The subsequent supercapacitor testing takes ~24 h and the Na ion battery testing takes ~72 h. The procedure is suitable for users with expertise in physics, chemistry, materials and other related disciplines.

Regulating the interconnected microporous structure of porous carbon by alkali metal ions for improved surface and space utilization for organic supercapacitors

Developing porous carbon with suitable microporous structure and large effective surface area is crucial for pursuing high volumetric performance of organic supercapacitors. Herein, we proposed a homogeneous activation method to regulate the interconnected microporous structure of porous carbon through choosing the alkali metal ion activators (Li+, K+, Cs+). We have revealed the pore evolution mechanism from the points of ion activation strength, cluster transport, and metal boiling points. Compared to others, the optimized sample activated by Cs+ shows large micropore volume, high effective surface area (2463 m2 g−1), and high compaction density (0.75 g cm−3), performing an improved volumetric capacitance (126 F cm−3 at 1 A g−1) and good rate performance (79 F cm−3 at 20 A g−1) in organic electrolyte. The symmetric supercapacitor at the commercial electrode mass loading shows a competitive energy density (23.9 Wh L−1 at 211.4 W L−1, 4 Wh L−1 at 1638 W L−1). Moreover, this pore-regulating strategy has a general availability when using other non-foaming carbon precursors, which will open up new paths for improving the surface and space utilization of porous carbon for compact capacitive energy storage.

Selective recognition of Fe2+ in aqueous solution by chalcones

Recognition of metal ions in aqueous media has direct impact for designing new supramolecular hosts for targeting biochemical pathways. In the present work we have studied the binding behavior of three simple chalcones with variation in number of phenolic OH groups. These chalcones showed very good binding capabilities towards metal ions in CH3OH-H2O (1:1, v/v) solvent system. The receptors R1 has interacted with all metal ions, which are used in the present study through 2:1 mode of complexation whereas R2 have showed equilibrium between the complexes of 2:1 and 1:1 with few exceptions. The highest association constants (K21) of R1 and R2 for Fe2+ is observed as 1.1 × 109 (4) M−1 and 2.3 × 108 (7) M−1 respectively by fluorescence titration method. But R3, which is lack of any phenolic OH group, binds all the metal ions through the formation of 1:1 mode of complex formation by exploiting the only one donor site as carbonyl ‘O’ atom resulting lower association constant for all the metal ions. So intermolecular hydrogen bonding as well as π- π stacking interaction forced the receptors R1 and R2 to arrange in a pseudo cleft orientation for the recognition of metal ions in 2:1 mode of complex formation. The binding behaviour of the receptors with few alkali metal ions (Na+, K+ and Cs+) and alkaline-earth metal ions (Mg2+, Ca2+ and Ba2+) are also studied and observed weak binding nature in compared with the transition metal ions.

High-Performance Alkali Metal Ion Storage in Bi2Se3 Enabled by Suppression of Polyselenide Shuttling Through Intrinsic Sb-Substitution Engineering.

Bismuth selenide holds great promise as a kind of conversion-alloying-type anode material for alkali metal ion storage because of its layered structure with large interlayer spacing and high theoretical specific capacity. Nonetheless, its commercial development has been significantly hammered by the poor kinetics, severe pulverization, and polyselenide shuttle during the charge/discharge process. Herein, Sb-substitution and carbon encapsulation strategies are simultaneously employed to synthesize SbxBi2-xSe3 nanoparticles decorated on Ti3C2Tx MXene with encapsulation of N-doped carbon (SbxBi2-xSe3/MX⊂NC) as anodes for alkali metal ion storage. The superb electrochemical performances could be assigned to the cationic displacement of Sb3+ that effectively inhibits the shuttling effect of soluble polyselenides and the confinement engineering that alleviates the volume change during the sodiation/desodiation process. When used as anodes for sodium- and lithium-ion batteries, the Sb0.4Bi1.6Se3/MX⊂NC composite exhibits superior electrochemical performances. This work offers valuable guidance to suppress the shuttling of polyselenides/polysulfides in high-performance alkali metal ion batteries with conversion/alloying-type transition metal sulfide/selenide anode materials.

Alkaline metal derived secondary thermal polymerization for superior thin g-C3N4 nanosheets with efficient photocatalytic performance

The thermal polymerization controlled the thickness and composition of graphic carbon nitride (g-C3N4) to affect the photocatalytic performance. In this paper, potassium and sodium ions were firstly incorporated in bulk g-C3N4 prepared using melamine through a mechano-chemical pre-reaction. After a two-step thermal polymerization treatment at 500 and 550 °C, respectively, superior thin g-C3N4 nanosheets were created because K or Na ions implanted between g-C3N4 layers, in which activated cites were remained in the nanosheets. The results revealed that potassium or sodium ion doping revealed an important impact on the photocatalytic activity of g-C3N4. With an optimized K loading of 3%, the hydrogen evolution rate of potassium doped g-C3N4 superior thin nanosheets was 18.1 times of that of bulk g-C3N4. For the degradation of the degradation rate of Rhodamine B (Rh B), K-doped g-C3N4 sample revealed 3.8 times increase compared with pure g-C3N4. To indicate the role of alkaline metal ions, Na-doped samples were also used for H2 generation and Rh B degradation. Meanwhile, the hydrogen generation and Rh B degradation rate of sodium doped g-C3N4 nanosheets improved to 3.6 and 1.75 times higher than those of pure g-C3N4, respectively. The result suggested a mechano-chemical pre-treatment helped K and Na ions to improve the microstructure of g-C3N4 nanosheets and increase activated cites for photocatalysis.

Preparation, luminescence, and application of LiMeBO3 borates, Me = Mg, Ca, Sr, Ba, Zn, Cd. Review

The review summarises and analyses data on the preparation, structure, and spectral-luminescent properties of LiMeBO3-based borates, Me = bivalent metal. These polycrystalline borates are prepared traditionally by solid-phase reactions and self-propagating high-temperature synthesis and its modifications based on a combustion reaction. Frameworks of lithium borates with alkaline earth metals, zinc, and cadmium are formed from large metal polyhedra between which there are boron-oxygen triangles isolated from each other. Doping with rare-earth and heavy metal ions leads to the formation of solid solutions which normally have defective structures. Doped activator ions often become the main part of the luminescence centre in the phosphor. The luminescent properties of ions of rare-earth elements arise from the possibility of electronic transitions between states within the 4f-configuration. The paper discusses the most likely mechanisms of charge compensation during heterovalent substitution in LiMeBO3 borates (co-doping and formationof cation vacancies). It is shown that charge compensation during the combined introduction of ions of REEs and alkali metals into the structure has a positive effect on the emission yield. The review considers the results of thermoluminescent, upconversion, and photoluminescent properties and processes and phenomena that cause them. It also explains the mechanism of resonance energy transfer from the sensitiser to the activator using the example of Yb3+→Er3+. It discusses the possibility of using the considered borates as phosphors that emit green, blue, and red light in white LEDs and as effective materials for personnel neutron dosimetry and the dosimetry of weak ionising radiation

Recent Progress of Self-Supported Metal Oxide Nano-Porous Arrays in Energy Storage Applications.

The demand for high-performance and cost-effective energy storage solutions for mobile electronic devices and electric vehicles has been a driving force for technological advancements. Among the various options available, transitional metal oxides (TMOs) have emerged as a promising candidates due to their exceptional energy storage capabilities and affordability. In particular, TMO nanoporous arrays fabricated by electrochemical anodization technique demonstrate unrivaled advantages including large specific surface area, short ion transport paths, hollow structures that reduce bulk expansion of materials, and so on, which have garnered significant research attention in recent decades. However, there is a lack of comprehensive reviews that discuss the progress of anodized TMO nanoporous arrays and their applications in energy storage. Therefore, this review aims to provide a systematic detailed overview of recent advancements in understanding the ion storage mechanisms and behavior of self-organized anodic TMO nanoporous arrays in various energy storage devices, including alkali metal ion batteries, Mg/Al-ion batteries, Li/Na metal batteries, and supercapacitors. This review also explores modification strategies, redox mechanisms, and outlines future prospects for TMO nanoporous arrays in energy storage.

Sodium and potassium ion storage in cation substituted 2D MoWSe2: insights into the effects of upper voltage cut-off

The superior properties, such as large interlayer spacing and the ability to host large alkali-metal ions, of two-dimensional (2D) materials based on transition metal di-chalcogenides (TMDs) enable next-generation battery development beyond lithium-ion rechargeable batteries. In addition, compelling but rarely inspected TMD alloys provide additional opportunities to tailor bandgap and enhance thermodynamic stability. This study explores the sodium-ion (Na-ion) and potassium-ion (K-ion) storage behavior of cation-substituted molybdenum tungsten diselenide (MoWSe2), a TMD alloy. This research also investigates upper potential suspension to overcome obstacles commonly associated with TMD materials, such as capacity fading at high current rates, prolonged cycling conditions, and voltage polarization during conversion reaction. The voltage cut-off was restricted to 1.5 V, 2.0 V, and 2.5 V to realize the material’s Na+ and K+ ion storage behavior. Three-dimensional (3D) surface plots of differential capacity analysis up to prolonged cycles revealed the convenience of voltage suspension as a viable method for structural preservation. Moreover, the cells with higher potential cut-off values conveyed improved cycling stability, higher and stable coulombic efficiency for Na+ and K+ ion half-cells, and increased capacity retention for Na+ ion half-cells, respectively, with half-cells cycled at higher voltage ranges.

Hydration of Alkali Metal and Halide Ions from Static and Dynamic Viewpoints.

Ion hydration in aqueous solutions plays a paramount role in many fields. Despite many studies on ion hydration, the nature of ion hydration is not consistently understood at the molecular level. Combining neutron scattering (NS), wide-angle X-ray scattering (WAXS), and molecular dynamics (MD), we quantify the ionic hydration degree (hydration ability) systematically for a series of alkali metal and halide ions based on static and dynamic hydration numbers. The former is based on the orientational correlation of water molecules bound to an ion derived from the positional information from NS and WAXS. The latter is defined as the mean number of water molecules remaining in the first coordination shell of an ion over a residence time of bound water molecules around the ion from MD. The static and dynamic hydration numbers distinguish hydration from coordination and quantify the ionic hydration degree, which provides a valuable reference for understanding various phenomena in nature.

Highly Utilized Active Sites on Pt@Cu/C for Ethanol Electrocatalytic Oxidation in Alkali Metal Hydroxide Solutions

AbstractUsing ethanol electrocatalytic oxidation reaction (EOR) with a lower reaction potential to replace oxygen evolution reaction (OER) and integrating hydrogen evolution reaction (HER) have a promising development prospect for more energy‐saving electrolytic hydrogen production. However, the main challenges of EOR are insufficient catalytic activity, high overpotential, and slow kinetics. Active sites on the electrocatalysts surface are occupied by alkali metal ion hydrate clusters by noncovalent interactions, which is considered to be one of the major causes of these challenges. To reduce the effect of the noncovalent interactions on the catalytic activity of the electrocatalyst, copper is chosen and doped in the form of a single atom in the electrocatalyst (Pt@Cu/C) to increase the electrocatalyst conductivity and make the anode contain more positive charge in this study. Then, alkali metal ion hydrate clusters are difficult to adsorb at the active site of Pt@Cu/C. The EOR electrocatalytic activity of Pt@Cu/C is up to 8184 mA mgPt−1, which is ≈4.8 times as high as that of Pt/C. The two‐electrode hydrogen production device using Pt@Cu/C as anode for coupled EOR&HER requires a smaller voltage of 0.60 V to reach 10 mA cm−2compared with that of Pt/C (0.76 V).

In-situ-grown multidimensional Cu-doped Co1-xS2@MoS2 on N-doped carbon nanofibers as anode materials for high-performance alkali metal ion batteries

Transition metal sulfides with the high theoretical capacity and low cost have been considered as advanced anode candidate for alkali metal ion batteries, but suffered from unsatisfactory electrical conductivity and huge volume expansion. Herein, a multidimensional structure Cu-doped Co1-xS2@MoS2 in-situ-grown on N-doped carbon nanofibers (denoted as Cu-Co1-xS2@MoS2 NCNFs) have been elaborately constructed for the first time. The bimetallic zeolitic imidazolate framework CuCo-ZIFs were encapsulated in the one-dimensional (1D) NCNFs through an electrospinning route and then on which the two-dimensional (2D) MoS2 nanosheets were in-situ grown via a hydrothermal process. The architecture of 1D NCNFs can effectively shorten ion diffusion path and enhance electrical conductivity. Besides, the formed heterointerface between MOF-derived binary metal sulfides and MoS2 can provide extra active centers and accelerate reaction kinetics, which guarantee a superior reversibility. As expected, the resulting Cu-Co1-xS2@MoS2 NCNFs electrode delivers excellent specific capacity of Na-ion batteries (845.6 mAh/g at 0.1 A/g), Li-ion batteries (1145.7 mAh/g at 0.1 A/g), and K-ion batteries (474.3 mAh/g at 0.1 A/g). Therefore, this innovative design strategy will bring a meaningful prospect for developing high-performance multi-component metal sulfides electrode for alkali metal ion batteries.

Efficient removal of alkali and alkaline earth metals from biodiesel using Ion-exchange resin: Performance and mechanism

Raw materials, production process, and other factors cause several metal ions to exist in biodiesel. Furthermore, the existence of alkali and alkaline earth metals seriously affects the quality and performance of biodiesel. To improve fuel quality, a 732 ion-exchange resin was used to reduce the contents of alkali and alkaline earth metal ions in Jatropha biodiesel. The adsorption efficiency of the ion-exchange resin for alkali and alkaline earth metal ions in biodiesel was evaluated using ion chromatography, while the adsorption mechanism of ion change resin on alkali and alkaline earth metal ions in biodiesel was elucidated via FTIR and XPS. In addition, the effects of ion-exchange resin on several key physiochemical properties of biodiesel, including oxidation stability, corrosivity, heat value and kinematic viscosity, were also explored. The results showed that the total content of alkali and alkaline earth metal ions in biodiesel was reduced by 88.19%, and the K+, Na+, Mg2+, and Ca2+ contents were reduced to 0.11 mg/kg, 0.89 mg/kg, 0.53 mg/kg, and 0.78 mg/kg, respectively, after removing the ion-exchange resin. In the removal process, the hydroxyl group of sulfonic acid group on the ion-exchange resin is broken, and the substitution adsorption reaction between H+ and the alkali and alkaline earth metal ions in biodiesel is carried out. Moreover, the oxidation induction period of biodiesel was prolonged by 40.8% owing to the reduction in the content of alkali and alkaline earth metal ions, which significantly blocked the decomposition pathways of unstable oxidation intermediates in biodiesel. The degree of copper corrosion in biodiesel did not change significantly before and after ion-exchange resin adsorption during short-term corrosion (3 h); however, the copper corrosion grade decreased from 2c to 1b after ion-exchange resin adsorption during long term corrosion (240 h). Nevertheless, the heat value and kinematic viscosity of biodiesel were observed to be independent of the ionic metal content.

Attachment of facile synthesized NaCo2O4 nanodots to SiO2 nanoflakes for sodium-rich boosted Pt-dominated ambient HCHO oxidation

Surface alkali metal ions are typically utilized as available promoters for ambient HCHO oxidation. In this study, NaCo2O4 nanodots with two different preferential crystallographic orientations are synthesized by facile attachment to SiO2 nanoflakes with varying degrees of lattice defects. A unique Na-rich environment is established through interlayer Na+ diffusion based on the small size effect. The optimized catalyst Pt/HNaCo2O4/T2 can deal with HCHO below 5 ppm in the static measurement system with a sustained release background and produces approximately 40 ppm of CO2 in 2 h. Combining the experimental analyses with density functional theory (DFT) calculations, the possible catalytic enhancing mechanism is proposed from the support promotion perspective, and the positive synergistic effect of Na-rich, oxygen vacancies and optimized facets for Pt-dominant ambient HCHO oxidation via both kinetic and thermodynamic processes is confirmed.

Alkali metal doped copper-sulfides as a new class electrocatalysts for oxygen evolution reaction

Copper sulfides (CuxS, x = 1 or 2) are extensively used in important reactions, including those involved in catalysis, superconductors, and biosensors. However, their oxygen evolution activity is much lower than that of other transition metal sulfides due to insufficient active sites and low intrinsic activity which limits their applicability in oxygen evolution reactions (OER). Therefore, it is essential to design effective strategies to enhance the OER performance of copper sulfides and understand their catalytic mechanisms. Here, A-Cu-S (A = Li, Na, K) is developed by introducing alkali metal ions (Li/Na/K) into CuxS (x = 1 or 2). Doping the alkali metal ions increases their electrical conductivity and optimizes the oxygenated intermediates' adsorption energy, improving the CuxS (x = 1 or 2) OER performance. The optimum overpotential of NaCu5S3 is 271@20 mA cm−2; much higher than Cu2S (> 450 mV), CuS (∼ 400 mV), and most other copper sulfides (300–400 mV). The improvement in the copper sulfide OER performance shows that the Li/Na/K doping strategy has an important and promising effect on the design of efficient copper sulfide electrocatalysts.

Investigation of the catalytic effect of defective Ni-MOF-74 on polymerization of dopamine and multi-pore polydopamine photothermal coating constructed with defective Ni-MOF-74 particles

Photothermal coating is an effective way to convert the seawater into fresh water, which is controlled by the light utilization capacity and micro-channel for the vaporation of water. In order to improve the effect of water evaporation and water purification driven by sunlight, polydopamine (PDA) coating with more micro-channel and high bonding was formed through the introduction of porous material and 3-Aminopropyltriethoxysilane (AMEO). Compared with Ni-MOF-74, defective Ni-MOF-74 could produce more coordination with dopamine and promote the polymerization of dopamine, resulting in the formation of sea cucumber structure, which is foundation for the micro-channel of the deposition coating of PDA. Also, depending on the sea cucumber structure, the as-prepared coating of PES/PDA/MOF-30 mg by the two-solvent strategy possesses the water evaporation rate of 1.85 kg/(m2·h), the photothermal conversion efficiency of 98.4%, the retention rate of alkali metal and heavy metal ions above 99% and good long-term stability. The coating with good comprehensive property is good choice for the water purification.

Alkali metal ion induced lattice regulation for all climate NASICON-type cathode with superior Na-storage performance

Na-ion batteries have been considered as promising candidates for future energy storage owing to Na availability and high-cost performance. However, their wide application is still hindered by poor rate capabilities, insufficient cycle lifespan and inferior variable-temperature performance. Here, we report an aliovalent-ion induced lattice regulation protocol with Li+, Na+, and K+ replacing V3+, which motivates the generation of electronic defects and expands the Na+ migration pathways. With the partial activation of V4+/V5+ redox, the prepared Na3V1.94K0.06(PO4)3 cathode exhibits capacity of 120.3 mAh g−1 at 0.1 C with remarkable capability (100.5 mAh g−1) and ultralong cycle stability (99.1 % capacity retention over 3000 cycles) at 20 C. Moreover, 96.9 % capacity retention after 200 cycles at 0.2 C for − 30 °C and discharge capacity of 127.8 mAh g−1 at 0.1 C for 55 °C were achieved for K+-substituted cathode. This work sheds lights on improving Na+ migration kinetics and clarifying the objective law for alkali metal ion doping in Na superionic conductor cathodes for wide-temperature batteries.

Steric Hindrance-Induced Dehydration Promotes Cation Selectivity in Trans-Subnanochannel Transport.

Dehydration is a basic phenomenon in ion transport through confined nanochannels, but how it affects ion trans-membrane selectivity has not been understood due to a lack of characterization techniques and suitable pore structures. Herein, hydration number distributions of typical alkali metal ions were characterized by combining uniform subnanochannels of ZIF-8-based membranes with the in situ liquid time-of-flight secondary ion mass spectrometry (ToF-SIMS) technique, revealing that steric hindrance induced ion dehydration through neutral confined ZIF-8 windows. The reduction in size due to partial dehydration increased the intrapore velocity for monovalent cations. The highest entropy value with maximum size changes resulting from dehydration drove fast and efficient selective transport of Li+ over other alkaline metal ions, leading to a Li+/Rb+ selectivity of 5.2. The dehydration at the entrance of membrane pores was shown to account for the majority of overall barriers, being a dominant element for ion transport. High hydration energy (>1500 kJ/mol) hindered the dehydration and transport of typical alkaline earth metal ions, achieving ultrahigh monovalent/bivalent cation selectivity (∼104). These findings uncover the crucial role of dehydration energy barriers and size-based entropy barriers in ion selectivity of trans-subnanochannel transport, providing guidelines for designing selective membranes with specific pore sizes to promote the dehydration of desired solutes.

Nano-Cavities within Nano-Zeolites: The Influencing Factors of the Fabricating Process on Their Catalytic Activities.

Titanium silicalite-1 (TS-1) is a milestone heterogeneous catalyst with single-atom tetrahedral titanium incorporated into silica framework for green oxidation reactions. Although TS-1 catalysts have been industrialized, the strategy of direct hydrothermal synthesis usually produces catalysts with low catalytic activities, which has still puzzled academic and industrial scientists. Post-treatment processes were widely chosen and were proven to be an essential process for the stable production of the high-activity zeolites with hollow structures. However, the reasons why post-treatment processes could improve catalytic activity are still not clear enough. Here, high-performance hollow TS-1 zeolites with nano-sized crystals and nano-sized cavities were synthesized via post-treatment of direct-synthesis nano-sized TS-1 zeolites. The influencing factors of the fabricating processes on their catalytic activities were investigated in detail, including the content of alkali metal ions, the state of titanium centers, hydrophilic/hydrophobic properties, and accessibility of micropores. The post-treatment processes could effectively solve these adverse effects to improve catalytic activity and to stabilize production. These findings contribute to the stable preparation of high-performance TS-1 catalysts in both factories and laboratories.

Unravelling the conductivity behaviour of thermally stable Li2O– Bi2O3–B2O3–P2O5 glasses embedded with V2O5

Solid state batteries are becoming more in demand owing to the advancement of EV technology. However, use of liquid electrolytes has become problematic due to their explosive nature. As a result, a lot of research is being done on solid electrolyte-based batteries (also known as “solid state batteries”) that employ glasses and alkali metal anodes consisting of Li+, Na+, K+. Herein we demonstrate the influence of V2O5 content on the conductivity characteristics along with their structural and thermal properties of melt-quenched V2O5-substituted lithium-bismuth-boro-phosphate glasses. The produced glasses were meticulously examined using XRD, FTIR, DTA, 11B-NMR, EPR, and impedance analyzer methods. Structural studies reveal the formation of non-crystalline/amorphous glasses having thermal stability up to 800 °C. Both FTIR and 11B-NMR results reveals the presence of borate groups, i.e., both BO4 and BO3. Additionally, EPR results exhibits hyperfine splitting of tetragonal V2O5, whose distortion varies with the content of V2O5 in the host glass. Furthermore, impedance and dielectric spectroscopy were used to explore the ac and dc conductivities in the frequency and temperature ranges 10 Hz - 3 MHz and 473–623 K respectively. The analyzed results show that both ac and dc conductivities increase with V2O5 content and the conductivity is more ionic in nature. Overall, the investigated results will enhance the fundamental understanding of conducting behaviour of glasses containing alkali and transition metal ions for the development of solid-state batteries.

2D Si-Ge layered materials as anodes for alkali-cation (Na+, K+) batteries

Recent studies have shown that two-dimensional (2D) materials, such as siloxene and germanane, as electrode in alkali metal ion batteries can lead to excellent performance. The improved electrochemical behavior of these 2D active materials could be due to the limited volume change during charge and discharge, based on an intercalation rather than an alloying mechanism. In addition, if Si is effective in reducing costs due to its low price and abundant resource reserves, its conductivity is low, while Ge can provide higher electronic conductivity than Si, but is more expensive. In this respect, in order to integrate their cheapness and excellent conductivity, we propose a series of layered materials (named siliganes, i.e., Si1-xGex, 0.1 ⩽ x ⩽ 0.9), which consist of 2D Si-Ge composites. Through a simple method, the Ca2+ cations were completely removed from the precursor Ca(Si1-xGex)2, and the lamellar siliganes were obtained. The layered materials were tested in Na- and K- ion batteries. Based on the better electrochemical performance, we identified siligane_Si0.1Ge0.9 as the best candidate. At a current density of 0.05 A g−1, its reversible capacities of the Na ion and K ion cells were 276 mAh g−1 and 132 mAh g−1 after 50 cycles, respectively.