Coordination Polymer Framework Research Articles

Mechanistic Understanding of Sieving Lithium Ions Using a Biobased Sorbent Technology for Sustainable Lithium Reclamation and Cleansing Brines.

Low-cost environmentally benign materials that can be produced in a large scale to extract lithium from brine resources could drive the lithium market toward a clean technology with high lithium recovery and production. Herein, we have investigated the utilization of a novel, environmentally benign, and low-cost biobased sorbent for the extraction of lithium from lithium-rich solutions. This biobased molecular sieving sorbent, iron(III)-tannate (Fe(III)-TA), belongs to a novel class of coordination polymer frameworks derived from a natural polyphenol-tannic acid (TA)-coordinated with iron(III) metal cations. Its lithium adsorption and kinetic isotherm studies conducted using lithium-rich aqueous solutions confirm the sorbent's dual function for lithium sieving via physisorption, chemisorption, and mass transfer diffusion processes. The adsorption equilibrium and kinetic isotherm models combined with the external and internal mass transfer diffusion models reveal a mechanistic pathway for lithium-ion adsorption. Aiding by forming a fluid film for external mass transfer diffusion of lithium ions, analytes adsorb onto the sorbent surface via physisorption and chemisorption followed by the internal mass transfer diffusion, occupying lithium ions in the sorbent's pores. The lithium adsorption efficiency studies conducted for brines with different concentrations of interference alkali and alkaline cations evidence that the sorbent's affinity for lithium ions strongly depends on the analyte concentration. The results evidence that the sorbent has the ability to lower the brine's salinity and significantly reduces the ratios of Mg/Li and Ca/Li by 4-fold and 10-fold, respectively, yielding lithium-rich solutions. Thus, implementing this innovative biobased sorbent technology as an add-in step into traditional lithium extraction and refining processes, one can design a cost-effective pathway to yield lithium-rich leachate by reducing the Mg/Li and Ca/Li ratio. Nonetheless, the present work demonstrates that Fe(III)-tannate is an effective multifunctional sorbent for sieving lithium from lithium-rich aqueous solutions as well as for desalinating brine resources to recover usable water. Thus, this biobased sorbent offers the possibility of effective application of lithium reclamation and remediation of brine, mitigating the environmental impact of brine discharge and large volume of freshwater usage for lithium extraction and refining.

Silver 2,4'-Bipyridine Coordination Polymer for the High-Capacity Trapping of Perrhenate, A Pertechnetate Surrogate.

Pertechnetate, the most stable form of the radionuclide 99Tc in aerobic aqueous systems, is a hazardous anion present in nuclear waste. Its high mobility in water makes the remediation of the anion challenging. In the past decade, significant effort has been placed into finding materials capable of adsorbing this species. Here, we present the synthesis and high-resolution crystal structure of the coordination polymer [Ag(2,4'-bipyridine)]NO3, which is capable of sequestering perrhenate─a pertechnetate surrogate─through anion exchange to form another new coordination polymer, [Ag(2,4'-bipyridine)]ReO4. Both the beginning and end structures were solved by single-crystal X-ray diffraction and the adsorption reaction was monitored through inductively coupled plasma-optical emission spectroscopy and UV-vis spectroscopy. The exchange reaction follows a pseudo-second-order mechanism and the maximum adsorption capacity is 764 mg ReO4/g [Ag(2,4'-bipyridine)]NO3, one of the highest recorded for a coordination polymer or metal-organic framework. A solvent-mediated recrystallization mechanism was determined by monitoring the ion-exchange reaction by scanning electron microscopy-energy-dispersive spectroscopy and powder X-ray diffraction.

Perylene-Based Coordination Polymers: Synthesis, Fluorescent J-Aggregates, and Electrochemical Properties.

The incorporation of electroactive organic building blocks into coordination polymers (CPs) and metal-organic frameworks (MOFs) offers a promising approach for adding electronic functionalities such as redox activity, electrical conductivity, and luminescence to these materials. The incorporation of perylene moieties into CPs is, in particular, of great interest due to its potential to introduce both luminescence and redox properties. Herein, we present an innovative synthesis method for producing a family of highly crystalline and stable coordination polymers based on perylene-3,4,9,10-tetracarboxylate (PTC) and various transition metals (TMs = Co, Ni, and Zn) with an isostructural framework. The crystal structure of the PTC-TM CPs, obtained through powder X-ray diffraction and Rietveld refinement, provides valuable insights into the composition and organization of the building blocks within the CP. The perylene moieties are arranged in a herringbone pattern, with short distances between adjacent ligands, which contributes to the dense and highly organized framework of the material. The photophysical properties of PTC-Zn were thoroughly studied, revealing the presence of J-aggregation-based and monomer-like emission bands. These bands were experimentally identified, and their behavior was further understood through the use of quantum-chemical calculations. Solid-state cyclic voltammetry experiments on PTC-TMs showed that the perylene redox properties are maintained within the CP framework. This study presents a simple and effective approach for synthesizing highly stable and crystalline perylene-based CPs with tunable optical and electrochemical properties in the solid state.

Structure and Magnetic Properties of Pseudo-1D Chromium Thiolate Coordination Polymers

The synthesis, structure, and magnetic properties of two novel, pseudo-one-dimensional (1D) chromium thiolate coordination polymers (CPs), CrBTT and Cr2BDT3, are reported. The structures of these materials were determined using X-ray powder diffraction revealing highly symmetric 1D chains embedded within a CP framework. The magnetic coupling of this chain system was measured by SQUID magnetometry, revealing a switch from antiferromagnetic to ferromagnetic behavior dictated by the angular geometrical constraints within the CP scaffold consistent with the Goodenough-Kanamori-Anderson rules. Intrachain magnetic coupling constants JNN of -32.0 and +5.7 K were found for CrBTT and Cr2BDT3, respectively, using the 1D Bonner-Fisher model of magnetism. The band structure of these materials has also been examined by optical spectroscopy and density functional theory calculations revealing semiconducting behavior. Our findings here demonstrate how CP scaffolds can support idealized low-dimensional structural motifs and dictate magnetic interactions through tuning of geometry and inter-spin couplings.

FeNi coordination polymer based highly efficient and durable bifunction oxygen electrocatalyst for rechargeable zinc-air battery

In the current field of electrochemistry, it is still a great challenge to develop bifunction oxygen electrocatalysts with low cost, high activity and long-lasting durability for rechargeable metal-air batteries. In this research, an excellent electrocatalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which was composed of nanostructured FeNi alloy nanoparticles inlaid on N-doped GOs-tangled porous carbon matrix (FeNi/N-GPCM), was prepared by pyrolyzing the Ni2+ ion doped bimetallic Fe-Ni coordination polymer (CP) with graphene oxide (GO) as template in the presence of melamine. Owing to the multilayer porous carbon structure and strong synergistic coupling between N-doped carbon species and FeNi alloy, the prepared electrocatalyst exhibited better catalytic performance (half-wave potential of 0.883 V and overpotential of 310 mV) than commercial Pt/C and RuO2. In addition, the Zinc-air battery prepared by the as-obtained bifunction-catalyst has a small charge–discharge voltage gap of 0.85 V, a high energy efficiency of 58.45 %, and an excellent cycling performance (400 h) at 10 mA cm−2 under ambient conditions. This work provided a great promising non-noble metal based multifunctional electrocatalyst for the storage and conversion of renewable energy and was very conductive for the design and synthesis of new CP or metal organic framework (MOF)-based electrocatalysts in the future.

Recent Advances of Silver-Based Coordination Polymers on Antibacterial Applications.

With the continuous evolution of bacteria and the constant use of traditional antibiotics, the emergence of drug-resistant bacteria and super viruses has attracted worldwide attention. Antimicrobial therapy has become the most popular and important research field at present. Coordination Polymer (CP) and/or metal-organic framework (MOF) platforms have the advantages of a high biocompatibility, biodegradability, and non-toxicity, have a great antibacterial potential and have been widely used in antibacterial treatment. This paper reviewed the mechanism and antibacterial effect of three typical MOFs (pure Ag-MOFs, hybrid Ag-MOFs, and Ag-containing-polymer @MOFs) in silver-based coordination polymers. At the same time, the existing shortcomings and future views are briefly discussed. The study on the antibacterial efficacy and mechanism of Ag-MOFs can provide a better basis for its clinical application and, meanwhile, open up a novel strategy for the preparation of more advanced Ag-contained materials with antibacterial characteristics.

Green Synthesis of De Novo Bioinspired Porous Iron-Tannate Microstructures with Amphoteric Surface Properties

Bioinspired porous microstructures of iron-tannate (Fe(III)-TA) coordination polymer framework were synthesized by catenating natural tannic acid with iron(II), using a scalable aqueous synthesis method in ambient conditions. The chemical composition, morphology, physiochemical properties, and colloidal stability of microstructures were elucidated. The surface area (SBET) and the desorption pore volume were measured to be 70.47 m2/g and 0. 44 cm3/g, respectively, and the porous structure was confirmed with an average pore dimension of ~27 nm. Microstructures were thermally stable up to 180 °C, with an initial weight loss of 13.7% at 180 °C. They exhibited high chemical stability with pH-responsive amphoteric properties in aqueous media at pH levels ranging from 2 to 12. Supporting their amphoteric sorption, microstructures exhibited rapid removal of Pb+2 from water, with 99% removal efficiency, yielding a maximum sorption capacity of 166.66 mg/g. Amphoteric microstructures of bioinspired metal–phenolate coordination polymers remain largely unexplored. Additionally, natural polyphenols have seldomly been used as polytopic linkers to construct both porous and pH-responsive amphoteric coordination polymer frameworks with a robust structure in both acidic and basic media. Thus, this de novo porous microstructure of Fe(III)-TA and its physiochemical surface properties have opened new avenues to design thermally and chemically stable, eco-friendly, low-cost amphoteric sorbents with multifunctionality for adsorption, ion exchange, separation, storage, and sensing of both anions and cations present in heterogeneous media.

A Novel 2D Conjugated Coordination Framework with a Narrow Bandgap for Micro‐Supercapacitors

The 2D conjugated coordination polymer frameworks (2D c‐CPFs), as a novel class of electronic materials, show significant potential in modern electronic devices. However, the lack of available construction monomers greatly hinders the development as well as the fundamental electronic process understanding of 2D c‐CPF in modern electronics. Herein, a novel conjugated coordination polymer framework is developed through coordination of a new planar ligand with copper ions. Benefiting from the in‐plane d–π conjugation and out‐of‐plane π stacking, as‐made coordination polymer framework exhibits a narrow bandgap of 1.12 eV. Then, a free‐standing hybrid layered film of coordination frameworks together with exfoliated graphene is prepared as the electrode for micro‐supercapacitors. The micro‐device displays the high areal specific capacitance of 14.3 mF cm−2, outperforming most of the reported conductive polymer‐based micro‐supercapacitors. Notably, the as‐prepared micro‐supercapacitor exhibits good electrochemical stability after 5000 cycles, as well as excellent flexibility for polyethylene terephthalate‐supported devices. Herein, not only is a novel d–π conjugated coordination polymer with narrow bandgap developed, but also its application in miniature and flexible devices is identified.

A Narrow Bandgap, Isocyanide‐Based Coordination Polymer Framework for Micro‐Supercapacitors with AC Line‐Filtering Performance

AbstractThe rapid expansion of wearable electronic devices boosts the development of energy storage minicomponents. Among them, the on‐chip micro‐supercapacitors (MSCs) have aroused widespread interest due to their distinctive characteristics, e.g., long cycle life, high power density, etc. Herein, an on‐chip MSC device is fabricated by using an isocyanide‐based coordination polymer framework as electrode material. Due to the narrow bandgap, flexibility, and compatibility of the coordination polymer, such MSC device with LiCl/PVA electrolyte delivers large capacitances (up to 0.98 mF cm−2 and 20.56 F cm−3 at a scan rate of 0.1 V s−1) and a short time constant (0.026 ms), which are comparable to the state‐of‐the‐art MSCs with polymer film electrodes. Moreover, this MSC device exhibits good AC line‐filtering ability (−70.8° at 120 Hz). This work introduces an implementable interfacial method to obtain coordination polymer frameworks for constructing miniaturized energy storage devices.

Coordination Polymer Framework-Derived Ni-N-Doped Carbon Nanotubes for Electro-Oxidation of Urea.

Electrochemical oxidation of urea (UOR) is critical in the removal of urea from wastewater and energy conservation and storage. Nickel-based catalysts are widely used for urea-ORR, but in all cases, the nickel must be hybridized with carbon materials to improve its conductivity. In this manuscript, we demonstrate the synthesis of a nickel-decorated carbon nanotube (Ni-NCNT) by simple microwave pyrolysis of Dabco (1,4-diazabicyclo[2.2.2]octane)-based coordination polymer frameworks (CPF). The surface structure, morphology and chemical composition of Ni-NCNT were characterized by Raman spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy (EDS) analysis. SEM studies showed micrometer-long bamboo-shaped CNTs with nickel nanoparticles anchored to the walls and inside the nanotubes. A structural study by TEM and Raman spectra showed that carbon nanotubes are rich in defects due to the presence of nitrogen, and this was confirmed by energy-dispersive X-ray spectroscopy (EDS) maps. When applied as electrocatalysts in urea oxidation reactions (UOR), our newly developed Ni-NCNT shows excellent electrocatalytic activity and stability, making it a versatile catalyst in energy generation and mitigating water contamination.

Viologen‐Based Uranyl Coordination Polymers: Anion‐Induced Structural Diversity and the Potential as a Fluorescent Probe

AbstractFour novel uranyl coordination polymers (CPs) have been synthesized by the utilization of viologen derivative ligand, 1,1’‐bis(3,5‐dicarboxyphenyl)‐4,4’‐bipyridinium (H4bdbp ⋅ 2Cl), and uranyl nitrate under hydrothermal reactions through the regulation of different kinds of inorganic acids (HF, HCl, HNO3, HClO4, H2SO4). Compound 1 features a unique triple‐stranded helix structure with a helical pitch of 31.578 Å. The ligands in compounds 2–4 have similar configurations, while their 3D structures are completely different due to the presence of different kinds of anions. The anions play different roles in the frameworks of these uranyl CPs. In addition, compound 2 possesses strong fluorescence both in solid‐state and aqueous suspension‐state. It is demonstrated that compound 2 can selectively detect Fe3+ over several competing metal cations in aqueous solution.

One amino-functionalized luminescence sensor demonstrating high sensitivity and selectivity for detecting Al3+ and Cu2+ as well as its luminescent mixed matrix membranes and test papers

A novel 3D Zn-based coordination polymer (NH2-LCU-110, LCU names Liaocheng University) with the formula [Zn(L1)(bpea)n (H2L1 ​= ​2-aminoterephthalic acid, bpea ​= ​1,2-bis(4-pyridyl)ethane), was hydrothermally synthesized from a flexible nitrogen-containing carboxylic acid ligand with various coordination modes as main ligands and nitrogen-containing auxiliary ligand with different structures. NH2-LCU-110 demonstrates an interesting 5-fold interpenetrating diamond structure. Luminescence measurements reveal that this complex has obvious emission enhancement and quenching towards Al3+ and Cu2+, respectively. The mixed matrix membranes (MMMs) incorporating NH2-LCU-110 and poly(methyl methacrylate) (PMMA) as well as simple test papers were both prepared for potential application. The MMMs can quickly detect Al3+ and Cu2+ and the original emission could be regenerated by lifting from the analytical solutions, demonstrating its fast response and good selectivity. The sensing mechanism was investigated in details by various measurements and compared with isostructural complex LCU-110 without –NH2 groups. All observations indicate that introduction of Lewis basic –NH2 groups can enhance the intermolecular interactions between the frameworks of coordination polymers and sensing analytes (Al3+ and Cu2+).

Development of heterogeneous catalysts and solid acid catalysts based on metal-organic framework (MOF) or porous coordination polymer (PCP)

Development of heterogeneous catalysts and solid acid catalysts based on metal-organic framework (MOF) or porous coordination polymer (PCP)

Catechol-Coordinated Framework Film-based Micro-Supercapacitors with AC Line Filtering Performance.

Coordination polymer frameworks (CPFs) have broad applications due to their excellent features, including stable structure, intrinsic porosity, and others. However, preparation of thin-film CPFs for energy storage and conversion remains a challenge because of poor compatibility between conductive substrates and CPFs and crucial conditions for thin-film preparation. In this work, a CPF film was prepared by the coordination of the anisotropic four-armed ligand and CuII at the liquid-liquid interface. Such film-based micro-supercapacitors (MSCs) are fabricated through high-energy scribing and electrolytes soaking. As-fabricated MSCs displayed high volumetric specific capacitance of 121.45 F cm-3 . Besides, the volumetric energy density of MSCs reached 52.6 mWh cm-3 , which exceeds the electrochemical performance of most reported CPF-based MSCs. Especially, the device exhibited alternating current (AC) line filtering performance (-84.2° at 120 Hz) and a short resistance capacitance (RC) constant of 0.08 ms. This work not only provides a new CPF for MSCs with AC line filtering performance but also paves the way for thin-film CPFs preparation with versatile applications.

Unsaturated coordination polymer frameworks as multifunctional sulfur reservoir for fast and durable lithium-sulfur batteries

Desirable sulfur electrochemistry strongly relies on host-guest interactions, which calls for rational designs on the surface fine structure of sulfur reservoir materials. Herein, we for the first time, explore the coordinative unsaturation in ferric hexacyanoferrate (FeHCF) for sulfur immobilization and catalyzation towards improved lithium-sulfur (Li–S) batteries. A simple ammonia etching treatment is implemented to selectively remove Fe III –H 2 O moieties, leaving vast coordinatively unsaturated Fe sites with a simultaneous establishment of considerable mesoporosity in the activated matrix (denoted as FeHCF-A). As a sulfur-host, the massive meso-scale channels endow FeHCF-A with abundant active interfaces and ion/mass transfer pathways, while more importantly, the coordinatively unsaturated Fe sites are revealed with higher adsorbability and conversion catalytic activity to polysulfides. Attributed to theses chemical and structural superiorities, the as-developed FeHCF-A enables a fast, stable, and efficient sulfur electrochemistry, e.g., good rate capability up to 5C and excellent cyclability with an ultralow decay rate of 0.024% per cycle over 500 cycles, as well as a commendable areal capacity of 4.5 mAh cm −2 under high sulfur loading. This work affords a new and insightful perspective of coordinative chemistry for material engineering in Li–S batteries as well as other related fields. The synergistically combination of unique porosity and unsaturated active Fe sites of FeHCF-A contributes to enhanced adsorption and rapid catalytic conversion of lithium polysulfides. • Ammonia etching method is firstly implemented to construct coordinatively unsaturated Fe sites. • The coordinatively unsaturated Fe sites contribute to enhanced adsorption and catalytic conversion of lithium polysulfides. • The mesoporosity in FeHCF-A enables the composite electrode with high sulfur loading and areal capacity.

0D to 3D Coordination Assemblies Engineered on Silver(I) Salts and 2‐(Alkylsulfanyl)azine Ligands: Crystal Structures, Dual Luminescence, and Cytotoxic Activity

The potential of 2‐(alkylsulfanyl)azine ligands for crystal engineering of functional Ag(I) complexes has been firstly demonstrated. The reaction of AgNO3, AgClO4 and AgOTf with 2‐(alkylsulfanyl)pyridines, ‐pyrimidines, and ‐quinolines gives a series of new Ag(I) compounds that range from mono‐ and dinuclear complexes to chain (1D), layered (2D) and framework (3D) coordination polymers (CPs). 2‐(Alkylsulfanyl)pyridines and ‐pyrimidines, depending on the reaction conditions, are assembled either into molecular complexes or CPs, while 2‐(alkylsulfanyl)quinolines afford dinuclear complexes exclusively. The most of compounds engineered feature site‐specific interactions such as Ag···Ag, Ag···O, and Ag···S ones. The 2‐(methylsulfanyl)quinoline (2‐MeSQn) complex, [Ag2(2‐MeSQn)2(NO3)2], displays room temperature intraligand (IL) phosphorescence, while the 2‐(methylsulfanyl)pyridine‐derived CPs emit dual luminescence expressed by IL fluorescence and phosphorescence. Moreover, cytotoxic activity of the compounds synthesized has been evaluated against hTERT lung fibroblasts, HeLa, MCF7, HepG2 and A549 cancer cells.

Crystal Structures and Melting Behaviors of 2D and 3D Anionic Coordination Polymers Containing Organometallic Ionic Liquid Components.

Although coordination polymers generally do not melt, several that do melt have been synthesized recently and have drawn much attention. In this study, two- and three-dimensional coordination polymers that melt were synthesized, [Ru(Cp)(C6 H5 R)][M{C(CN)3 }2 ] (R=H, Me, Et; M=K, Rb; Cp=C5 H5 ), which are complex salts comprising M[C(CN)3 ] and organometallic ionic liquids [Ru(Cp)(C6 H5 R)][C(CN)3 ]. They have anionic [M{C(CN)3 }2 ]n - coordination polymer frameworks, whose dimensionalities depend on the size of the organometallic cation inside. Their melting points decreased with increasing cation substituent length and size of the alkali metal ion (Tm =102-239 °C), and these low-melting-point coordination polymers exhibited incongruent melting, forming mixtures of solid M[C(CN)3 ] and ionic liquid upon melting. Using the same method, coordination polymers were synthesized with various bridging ligands, [Co(Cp)2 ][MX2 ] (X=B(CN)4 , C(CN)3 , N(CN)2 ; M=K, Na), as well as a paramagnetic coordination polymer, [Fe(Cp)2 ][K{C(CN)3 }2 ].

Synthesis, Crystal Structure and Thermal Property of Two New Coordination Polymers with Ligands Containing Both N and O Donors

Two new metal–organic coordination polymer frameworks formulated as, {[Co(nta)]·H3O+}n (1), and {[Zn(ina)Cl2]·H3O+·H2O}n (2) (nta = nitriliotriacetic acid, ina = isonicotinate), have been synthesized under mild conditions and characterized by elemental analyses, IR spectrum, PXRD, thermal gravimetric analysis (TG) and single-crystal X-ray diffraction. Complex 1 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters a = 8.403(4) A, b = 10.165(5) A, c = 11.230 A, β = 90, V = 959.3(9) A3. Complex 2 crystallizes in the monoclinic space group P2(1)/c with unit cell parameters a = 7.1334(13) A, b = 22.369(4) A, c = 7.0089(13) A, β = 101.099(2), V = 1097.5(3) A3. In fact, 1 is a new 3D cobalt complex with the nta ligands acted as bridges to form network polymer. Each nta ligand bonds to three cobalt ions, and each cobalt ion coordinates with three nta ligands in different directions. 2 displays a new 1D zigzag chain linked by ina ligand and an interesting 1D hydrogen-bond infinite chain consists of seven-membered rings and four-membered rings. These chains are further linked to generate a new 3D framework. Two novel metal–organic coordination polymer frameworks have been synthesized under mild conditions and characterized by elemental analyses, IR spectrum, PXRD, thermal gravimetric analysis (TG) and single-crystal X-ray diffraction.

Vacancy modification of Prussian-blue nano-thin films for high energy-density micro-supercapacitors with ultralow RC time constant

In-plane micro-supercapacitors (MSCs), as promising power candidates for micro-devices, typically exhibit high power densities, large charge/discharge rates, and long cycling lifetimes. The high areal/volumetric capacitances, high energy/power densities, high rate capability, as well as flexibility are the main scientific pursue in recent years. Among diverse electrode materials for MSCs, coordination polymer frameworks are emerging due to the designable porous structure and tunable functionality. However, the unsatisfied electrochemical performance still hinders their practical applications. In this work, we demonstrate the first time an efficient in-situ growth approach to precisely modify the vacancy of Prussian-blue nano-thin films with pyridine by coordination reaction for high energy-density MSCs. Confirmed by the experimental results and density functional theory calculation, the vacancy modification within Prussian-blue network improved the film-forming property, hydrophilicity, and electrochemical activity of the thin films. The resultant MSCs based on pyridine-modified Prussian-blue exhibited an ultrahigh energy density of up to 12.1 mWh cm−3 and an ultra-low time constant (τ0) of 0.038 ms, which are the best values among the state-of-the-art in-plane MSCs. This work provides an attractive solution for structural engineering of promising active materials on molecule level toward high-performance micro-energy devices.

Metal Coordination Polymer Framework Governed by Heat of Hydration for Noninvasive Differentiation of Alkali Metal Series.

We illustrate that the extent of hydration and consequently the heat of hydration of alkali metal ions can be utilized to control their insertion/deinsertion chemistry in a redox active metal coordination polymer framework (CPF) electrode. The formal redox potential of CPF electrode for cation intercalation is inversely correlated to hydrated ionic radii, with clear distinction between the intercalation of ions across alkali metal series. This leads to noninvasive identification and differentiation of cations in the alkali metal series by utilizing a single sensing platform.