Borate Anion Research Articles

Nonflammable, robust and flexible electrolytes enabled by phosphate coupled polymer–polymer for Li-metal batteries

Liquid organic electrolytes commonly employed in commercial Li-ion batteries suffer from safety issues such as flammability and explosions. Replacing liquid electrolytes with nonflammable electrolytes has become increasingly attractive in the development of safe, high-energy Li-metal batteries (LMBs). In this work, nonflammable, robust, and flexible composite polymer–polymer electrolytes (PPEs) were successfully fabricated by flame-retardant solution casting with polyimide (PI) and polyvinylidene fluoride (PVDF). The optimized nonflammable PPEs (e.g., PPE-50) demonstrate not only good mechanical properties (i.e., a high tensile strength of 29.6 MPa with an elongation at break of 87.2%), but also high Li salts dissolubility, the former of which ensures the suppression of Li dendrites, while the latter further improves the ionic conductivity (∼1.86 × 10−4 S cm−1 at 30 °C). The resulting symmetric cells (Li|PPE-50|Li) offer excellent Li stripping and plating stability for 1000 h at 0.5 mA cm−2/0.25 mAh cm−2 and 600 h at 2.0 mA cm−2/1.0 mAh cm−2. In addition, the LiFePO4|PPE-50|Li half cells show high cycling performance (e.g., a reversible discharge capacity of 135.9 mAh g−1 after 300 cycles at 1C) and rate capability (e.g., 117.2 mAh g−1 at 4C). The PPE-50 is also compatible with a high-voltage cathode (e.g., LiNi0.5Mn0.3Co0.2O2), and the resulting batteries demonstrate long-term cycling stability with a high cut-off voltage of 4.5 V vs. Li/Li+. Because of the incorporation of a mechanically robust and thermally stable PI, a polar PVDF, and flame-retardant trimethyl phosphate (TMP) within PPEs, as well as the coordination between Li salts and TMP, and the interaction between Li salts and polymers (especially between Li bis(oxalato)borate) and PI, as well as the bis(oxalato)borate anion and PI), PPEs show great potential for practical and high-energy LMBs without safety concerns.

Reactivity, stability, and thermodynamics of para-methylpyridinium-based ionic liquids: Insight from DFT, NCI, and QTAIM

Ionic liquids (ILs) have lately piqued scientific attention due to their potential applications in green transition technologies such as catalysis, electrochemistry, and photovoltaic. The investigation of structural stability, reactivity, topological analysis, and thermodynamics of 4-methylpridine (4-picoline) based ILs is carried out using an advanced computational electronic structure theory technique based on first principle density functional theory (DFT). The ILs were modeled based on the interaction of 4-methylpridine (4-picoline) ion (cation) with borate, nitrate, phosphate, carbonate, and sulfate anions which have been chemically symbolized respectively as follows: [PMHP]+[HBO3]−, [PMHP]+[HNO3]−, [PMPH]+[HPO3]−, [PHMP]+[HCO3]−, and [PHMPM]+[HSO4]−. The energy difference between HOMO - LUMO of the studied compounds were found to show a general decreasing trend in the order: [PMHP][H2BO3] > [PMHP][NO3]> [PMPH][H2PO3]> [PHMP][HCO3]> [PHMPM][HSO4] with the borate ([PMHP][H2BO3]) and sulfate ([PHMPM][HSO4]) ILs having the relatively highest and least energy gap of 6.30 and 4.14 eV respectively. Strong interaction energies of 329.50 kca/mol, 114.41 kcal/mol, 107.12 kcal/mol, 98.19 kcal/mol and 87.86 kcal/mol involving the bonding, anti – bonding and lone pair orbitals associated with the pair of ILs were obtained as a trend: [PMHP][HSO4] > [PMHP][HCO3] > [PMPH][H2BO3] > [PHMP][NO3] > [PHMPM][H2PO3]. The intermolecular hydrogen bond (H-bond) analysis between the cation and anions ILs pairs obtained from quantum theory of atoms-in-molecules (QTAIM) reveals strong, weak, and electrostatic bonds. [PMPH]+[HSO4]− ILs pair was observed to possess the highest binding energy of -20.06 kcal/mol in the same way energy decomposition analysis (EDA) reveals a relatively strong orbital interaction in the [PMPH][HSO4] ILs due to the increase in electrostatic interaction of the four O-atoms in the sulfate anion, the analysis of the thermodynamic results indicates that the syntheses of the ILs are exothermic and spontaneous.

Interplay among Hexafluorophosphate, Difluoro(oxalato)borate Anions and Ethylene Carbonate during Their Insertion into a Graphite Electrode.

Ethylene carbonate solutions dissolving mixed lithium salts composed of both difluoro(oxalato)borate (DFOB-) and hexafluorophosphate (PF6-) anions are introduced into Li/graphite cells. The anions' intercalation procedures into the graphite positive electrode from these solutions are explored by charge/discharge, cyclic voltammetry, and impedance spectroscopic tests in combination with electrochemical in situ characterization including X-ray diffraction (XRD) and Raman spectroscopy. Furthermore, these solutions are characterized by ionic conductivity together with nuclear magnetic resonance measurements. The properties of the solutions are linked to the capacity values delivered by Li/graphite cells.

Rh-Catalyzed Coupling of Aldehydes with Allylboronates Enables Facile Access to Ketones.

We present herein a novel strategy for the preparation of ketones from aldehydes and allylic boronic esters. This reaction involves the allylation of aldehydes with allylic boronic esters and the Rh-catalyzed chain-walking of homoallylic alcohols. The key to this successful development is the protodeboronation of alkenyl borylether intermediate via a tetravalent borate anion species in the presence of KHF2 and MeOH. This approach features mild reaction conditions, broad substrate scope, and excellent functional group tolerance. Mechanistic studies also supported that the tandem allylation and chain-walking process were involved.

A new salt-inclusion compound, |Ag4Br|@[B7O12], with a novel type of the porous double-layered borate anion and strong anharmonicity of the “guest” sublattice

A new triclinic layered borate, |Ag4Br|@[B7O12], has been prepared by glass crystallization and slow cooling stoichiometric melts in evacuated silica ampoules. The structure is based upon a layered borate anion 7:∞2 [(4: 2Δ + 2 T) + (3: 2Δ + T)] with an architecture yet not observed among inorganic borates. The layers consist of two parts comprised of tri- and tetraborate groups; it is ∼7 Å thick and oriented parallel to (001). The interlayer space is filled by the cationic [Ag4Br]3+sublattice exhibiting disorder and anharmonicity at the silver sites. The new compound was characterized by thermal analysis, high-temperature powder X-ray diffraction, vibrational and UV–Vis–NIR spectroscopy, as well as DFT calculations. For the triclinic unit cell, the eigenvalues of the thermal expansion tensor and the orientation of the thermal expansion tensor relative to the crystallographic axes are determined. The thermal expansion of the new borate bromide is strongly anisotropic, being marginal in the plane of the B–O layers (α11 = 8.2 (1), α22 = 4.71 (3) × 10−6 °С−1) while quite large in the normal direction (α33 = 38.2 (3) × 10−6).

Chiral Binaphthyl‐Based Iodonium Salt (Hypervalent Iodine(III)) as Hydrogen‐ and Halogen‐Bonding Bifunctional Catalyst: Insight into Abnormal Counteranion Effect and Asymmetric Synthesis of N,S‐Acetals

AbstractAsymmetric construction of chiral N,S‐acetal skeletons is important because they are widely present in natural products and pharmaceuticals. Halogen‐bonding is a unique interaction that has been an organic synthesis focus, although research into chiral variants is limited. Halonium salts have been found to act as halogen‐bonding catalysts and asymmetric catalysis using chiral bromonium salts under basic conditions was recently discovered by our group. Herein, we report the asymmetric syntheses of chiral N,S‐acetals in good‐to‐excellent yields and enantioselectivities (82–97% ee) through bulky thiol additions to imines catalysed by a chiral iodonium salt under neutral conditions. The reaction mechanism was studied using NMR experiments and DFT calculations of a plausible intermediate, which revealed that the imine substrate is activated by the catalyst in a bidentate manner. The abnormal counteranion effect observed for the tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate anion in the present system was examined by 1H NMR spectroscopy.magnified image

Electrochemical water oxidation catalyzed by a mononuclear cobalt complex of a pentadentate ligand: the critical effect of the borate anion

A cobalt complex is found as a homogeneous water oxidation electrocatalyst. Electrochemical examinations indicate that the implementation of proton-couple electron transfer process and formation of O–O bond are assisted by borate anion.

Rhodium and Iridium Complexes of Anionic Thione and Selone Ligands Derived from Anionic N-Heterocyclic Carbenes.

The lithium salts of anionic N‐heterocyclic thiones and selones [{(WCA‐IDipp)E}Li(toluene)] (1: E=S; 2: E=Se; WCA=B(C6F5)3, IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene), which contain a weakly coordinating anionic (WCA) borate moiety in the imidazole backbone were reacted with Me3SiCl, to furnish the silylated adducts (WCA‐IDipp)ESiMe3 (3: E=S; 4: E=Se). The reaction of the latter with [(η 5‐C5Me5)MCl2]2 (M=Rh, Ir) afforded the rhodium(III) and iridium(III) half‐sandwich complexes [{(WCA‐IDipp)E}MCl(η 5‐C5Me5)] (5–8). The direct reaction of the lithium salts 1 and 2 with a half or a full equivalent of [M(COD)Cl]2 (M=Rh, Ir) afforded the monometallic complexes [{(WCA‐IDipp)E}M(COD)] (9–12) or the bimetallic complexes [μ 2‐{(WCA‐IDipp)E}M2(COD)2(μ 2‐Cl)] (13–16), respectively. The bonding situation in these complexes has been investigated by means of density functional theory (DFT) calculations, revealing thiolate or selenolate ligand character with negligible metal‐chalcogen π‐interaction.

Volume Increments for Crystalline Borates

AbstractA set of volume increments for ionic oxido‐borates is developed for trigonal‐planar and tetrahedral coordinated boron fragments in densely packed crystal structures. For this purpose, the cell volume of 277 alkaline‐ and earth alkaline borate structures was analyzed with respect to the volume of different anionic borate building units. The volume increments help to determine the number of formula equivalents in a cell which is especially useful for the structure solution process starting from powder diffraction data. This was demonstrated on a new methylammonium borate, [H3CNH3]B5O6(OH)4 ⋅ CH3NHCOH which could be solved from powder X‐ray diffraction data. The compound crystallizes in the monoclinic space group P 1 21/c 1 with the lattice parameters a=7.3040(1) Å, b=11.6377(1) Å, c=17.1065(3) Å, β=107.2167(9)° and Z=4. The structure model is supported as well by 1H, 11B, 13C and 15N solid‐state NMR and quantum chemical calculations.

Hierarchical ultrathin NiFe-borate layered double hydroxide nanosheets encapsulated into biomass-derived nitrogen-doped carbon for efficient electrocatalytic oxygen evolution

Exploring highly efficient, cost-effective, and stable electrocatalysts toward oxygen evaluation reaction (OER) is of great significance for hydrogen generation. Herein, in situ growth of NiFe-borate layered double hydroxide (NiFe-BLDH) nanosheets on waste biomass-derived nitrogen-doped carbon (NC) with hierarchical architecture under microwave hydrothermal conditions is reported. The as-synthesized NiFe-borate layered double hydroxide/nitrogen-doped carbon (NiFe-BLDH/NC) exhibits outstanding OER activity, showing an extremely low overpotential of 243 mV at the current density of 10 mA cm−2 and a relatively small Tafel slope of 42.7 mV dec−1, which are superior to the commercial RuO2 and many previously reported NiFe-LDH-based OER electrocatalysts. Additionally, the catalyst also shows remarkable stability with unobvious decrease of current density over a period of 24 h. These excellent catalytic performances could be attributable to the synergistic effects between the conductive NC scaffold and NiFe-BLDH with excellent hydrophilicity caused by the intercalated borate anions, which provide many advantages, such as large surface area, abundant active sites, fast charge and mass transport pathways. This work provides new insights into the design and facile preparation green and efficient electrocatalysts

Design of a Single-Ion Conducting Polymer Electrolyte for Sodium-Ion Batteries

A sodium bis(fluoroallyl)malonato borate salt (NaBFMB) is synthesized. Using a Click thiol-ene reaction, NaBFMB can be photo-crosslinked with a tri-thiol (trimethylolpropane tris(3-mercapto propionate), TMPT) to create a single-ion conducting electrolyte (NaSIE), with all negative charges residing on the borate moieties and anions immobilized through the 3-D crosslinked network. The NaSIE can be prepared either as a free-standing film or through a drop-cast method followed by a photo crosslinking method for an in-situ formation on top of the electrodes. The free-standing film of NaSIE has a high ionic conductivity of 2 × 10−3 S cm−1 at 30 °C, and a high transference number (tNa +) of 0.91 as measured through the Bruce-Vincent method. The electrochemical stability of NaSIE polymer electrolyte is demonstrated via cyclic voltammetry (CV) to be stable up to 5 V vs Na/Na+. When tested inside a symmetrical Na//Na cell, the NaSIE shows a critical current density (CCD) of 0.4 mA cm−2. The stability of NaSIE is further demonstrated via a long cycling of the stripping/plating test with a current density of 0.1 mA cm−2 at five-minute intervals for over 10,000 min. Using the in-situ method, NaSIE is used as the electrolyte for a sodium metal battery using P2 (Na resides at prismatic sites with with ABBAAB stacking)-cathode of Na0.67Ni0.33Mn0.67O2 (NNMO) and is cycled between the cut-off voltages of 2.0–4.0 V. A high initial specific capacity (85.7 mAh g−1) with a capacity retention of 86.79% after 150 cycles is obtained.

Impact of the anion on electrochemically doped regioregular and regiorandom poly(3‐hexylthiophene)

AbstractChemical and electrochemical doping of π‐conjugated polymers is an important aspect in determining the performance and enabling the operation of many organic electronic devices, from organic light emitting diodes and thermoelectrics to organic electrochemical transistors. In both chemical doping and electrochemical doping an ionized dopant or counterion is present along with the doped π‐conjugated polymer. This dopant or counterion is not a benign spectator, rather, its presence can significantly impact the optical, electronic, and thermoelectric properties of the resulting material. Here, we investigate how counterion structure impacts the electrochemical doping ability, oxidation potential, ionization energy, and polaron absorbance of regioregular (rr) and regiorandom (rra) P3HT. We find that in most cases the anion has a small effect on the polymer oxidation potential, except for in the case of rr‐P3HT with the large tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate anion. We propose that this large anion is excluded from the crystalline regions and thus the oxidation potential is similar to that of rra‐P3HT. The anions also result in significant differences in polaron absorbance and ionization energies, thereby emphasizing the important role of the counterion in determining the optical and electronic properties of doped π‐conjugated polymers.

Yttrium and rare-earth modified lithium orthoborates: Glass formation and vibrational activity

Glass formation and structure-property relations were explored in highly modified borate glasses containing high loads of rare-earth elements, whose crystalline analogues display a trigonal to tetrahedral borate phase transition (BO33− → BØ2O23−, where Ø and O− indicate bridging and non-bridging oxygen atoms). The resulting borate networks are completely depolymerized, where borate anions are crosslinked to rare-earth and modifier cations via ionic bonds. The borate structure was found to be based on a single structural unit, BO33− triangles, whose fundamental vibrations are all active in both the Raman and infrared. The local environment of the rare-earth ions in orthoborate glasses was studied with far infrared spectroscopy and, in some cases, by using terbium as a probe ion. A linear correlation was obtained between the effective force constant in the far infrared and the field strength of the rare-earth cation.

Fluorinated Boron-Based Anions for Higher Voltage Li Metal Battery Electrolytes.

Lithium metal batteries (LMBs) require an electrolyte with high ionic conductivity as well as high thermal and electrochemical stability that can maintain a stable solid electrolyte interphase (SEI) layer on the lithium metal anode surface. The borate anions tetrakis(trifluoromethyl)borate ([B(CF3)4]−), pentafluoroethyltrifluoroborate ([(C2F5)BF3]−), and pentafluoroethyldifluorocyanoborate ([(C2F5)BF2(CN)]−) have shown excellent physicochemical properties and electrochemical stability windows; however, the suitability of these anions as high-voltage LMB electrolytes components that can stabilise the Li anode is yet to be determined. In this work, density functional theory calculations show high reductive stability limits and low anion–cation interaction strengths for Li[B(CF3)4], Li[(C2F5)BF3], and Li[(C2F5)BF2(CN)] that surpass popular sulfonamide salts. Specifically, Li[B(CF3)4] has a calculated oxidative stability limit of 7.12 V vs. Li+/Li0 which is significantly higher than the other borate and sulfonamide salts (≤6.41 V vs. Li+/Li0). Using ab initio molecular dynamics simulations, this study is the first to show that these borate anions can form an advantageous LiF-rich SEI layer on the Li anode at room (298 K) and elevated (358 K) temperatures. The interaction of the borate anions, particularly [B(CF3)4]−, with the Li+ and Li anode, suggests they are suitable inclusions in high-voltage LMB electrolytes that can stabilise the Li anode surface and provide enhanced ionic conductivity.

Promoting Persistent Superionic Conductivity in Sodium Monocarba-closo-dodecaborate NaCB11H12 via Confinement within Nanoporous Silica.

Superionic phases of bulk anhydrous salts based on large cluster-like polyhedral (carba)borate anions are generally stable only well above room temperature, rendering them unsuitable as solid-state electrolytes in energy-storage devices that typically operate at close to room temperature. To unlock their technological potential, strategies are needed to stabilize these superionic properties down to subambient temperatures. One such strategy involves altering the bulk properties by confinement within nanoporous insulators. In the current study, the unique structural and ion dynamical properties of an exemplary salt, NaCB11H12, nanodispersed within porous, high-surface-area silica via salt-solution infiltration were studied by differential scanning calorimetry, X-ray powder diffraction, neutron vibrational spectroscopy, nuclear magnetic resonance, quasielastic neutron scattering, and impedance spectroscopy. Combined results hint at the formation of a nanoconfined phase that is reminiscent of the high-temperature superionic phase of bulk NaCB11H12, with dynamically disordered CB11H12– anions exhibiting liquid-like reorientational mobilities. However, in contrast to this high-temperature bulk phase, the nanoconfined NaCB11H12 phase with rotationally fluid anions persists down to cryogenic temperatures. Moreover, the high anion mobilities promoted fast-cation diffusion, yielding Na+ superionic conductivities of ∼0.3 mS/cm at room temperature, with higher values likely attainable via future optimization. It is expected that this successful strategy for conductivity enhancement could be applied as well to other related polyhedral (carba)borate-based salts. Thus, these results present a new route to effectively utilize these types of superionic salts as solid-state electrolytes in future battery applications.

Unexpected Formation of the Highly Symmetric Borate Ion [B(SiCl3)4]−

AbstractDisproportionation reactions of chlorosilane compounds in the presence of boron trichloride yield the compound H[B(SiCl3)4]. Spectroscopic analyses of the yellow‐whitish solid with IR‐, Raman‐, and NMR‐spectroscopy (29Si, 11B) show the presence of a highly symmetric anion containing boron, which is fourfold coordinated with silicon. Due to the high symmetry 1J(11B,29Si) and even 1J (10B, 29Si) couplings can be observed in the NMR spectra of the dissolved compound. The crystal structure analysis with a crystal obtained from toluene solution proves the existence of a highly symmetric borate anion, which is stabilized by four trichlorosilyl groups. The molecular structure consists of a para‐protonated toluene cation and the weakly coordinating borate anion [B(SiCl3)4]−. Quantum chemical analysis of the tetrakis(trichlorosilyl)borate ion shows a negatively charged boron atom and the presence of polar Si−Cl and Si−B bonds. Highly reactive compounds [E(SiCl3)n]− which are stabilized solely by trichlorosilyl groups have been prepared with E=C, Si, Ge, P, S in recent years. The superacid H[B(SiCl3)4] represents a new member in this elusive compound family.

Borate Anion Dopant Inducing Oxygen Vacancies over Co3O4 Nanocages for Enhanced Oxygen Evolution

The rational design of cost effective and highly efficient oxygen evolution reaction (OER) catalysts plays an extremely important role in promoting the commercial applications of electrochemical water splitting. Herein we reported a sacrificial template strategy for the preparation of borate anion doped Co3O4@ZIF-67 nanocages assembled with nanosheets (B-Co3O4@ZIF-67) by hydrothermal boronation of zeolitic imidazolate framework-67 (ZIF-67). During the preparation process, two different kinds of borate anion sources were found to regulate the morphological structures by tuning the etching rate between ZIF precursors and the borate anion. Moreover, borate anion doping was also found to induce oxygen vacancy defects, which is beneficial for modulating the electronic structure and accelerating electron transport. Meanwhile, the resultant B-Co3O4@ZIF-67 nanocages possess a large specific surface area, which is beneficial for the mass transfer of the electrolyte and exposing more catalytic active sites. Benefiting from the advantages above, the resultant B-Co3O4@ZIF-67 nanocages exhibit impressive OER performance with a small overpotential of 334 mV, a current density of 10 mA cm−2, a small Tafel slope of 73.88 mV dec−1, as well as long-term durability in an alkaline electrolyte.

Organoboron compounds as versatile reagents in the transition metal-catalyzed C–S, C–Se and C–Te bond formation

• Coupling reaction using organoboron compounds. • Organometallic catalysis and coordination. • Different methods for obtaining a new Carbon–Chalcogen bond. • Coupling reactions between different sources of chalcogen and organoboron reagents. Organochalcogen compounds present synthetic and biological applications of extreme relevance. The coupling reaction between boronic acids, borate anions or boronic esters with different sources of chalcogen (S, Se and Te), mediated by transition metals, is a powerful tool for the formation of functionalized diorganyl chalcogenides. By this strategy, selenides, sulfides, and tellurides with high complexity and molecular diversity can be prepared in good to excellent yields. This review covers the use of organoboron compounds as a versatile reagent for the formation of Carbon–Chalcogen bonds using different metallic catalysts (Cu, Ag, Pd, Fe, In, Rh, Ni).

NOVEL NON-AQUEOUS ELECTROLYTES BASED ON COORDINATION BORON COMPOUNDS

The review provides a classification of electrolytes for modern chemical power sources, supercapacitors, sodium and lithium-ion batteries depending on changes in the physicochemical properties of salts and the products of their interaction with the solvent. A comparative analysis of physicochemical properties of salts depending on the structure of the cation and anion, and the influence of these properties on the properties of final solutions of electrolytes on the example of different classes of ionic liquids and chelatoborates of alkali metals and ammonium was conducted. The dependence of the physicochemical properties of electrolytes (solubility, electrical conductivity of solutions and the range of potentials of electrochemical stability) on the nature of the chelate ligand, electron donor and electroacceptor substituents in the bis (chelate) borate anion is analyzed. The electrical conductivity of salt solutions and ranges of potentials of electrochemical stability of the corresponding electrolytes containing other anions and used for a long time in chemical current sources are carried out. The advantages and disadvantages of using liquid electrolytes compared to solid and polymer electrolytes in terms of similarity of their structures have been detected. It is shown that the nature of the chelate ligand, electro-donor and electro-acceptor substituents in the bis (chelato) borate anion is an important factor in regulating the interaction with aprotic dipolar solvents. Mixed salts with two different chelate ligands typically combine the best characteristics of the corresponding monochelate compounds, but the methods for their preparation and purification are technologically significantly more complex compared to monochelate compounds. The analysis of the mechanism of formation of a protective film on a surface of electrode materials, dependence of potential on its formation and on the chemical nature of ligands is made. It is noted that bis (chelato) borate salts are more environmentally friendly compared to fluorine-containing complex salts. Emphasis is placed on the physicochemical properties of solutions of the most promising chelatoborate salts for use in lithium and sodium ion batteries, supercapacitors and electrolytic capacitors, and it is shown that bis (oxalate) borates and bis (salicylate gold) borates occupy ) borates in terms of electrical conductivity, solubility and potential range of electrochemical stability.

Preparation of hollow hierarchical porous CoMgAl-borate LDH ball-flower and its calcinated product with extraordinary adsorption capacity for Congo red and methyl orange

Three-dimensionally ordered hollow borate anions intercalated CoMgAl-LDH ball-flower with hierarchical porous structure have been prepared by using zeolitic imidazolate framework-67 (ZIF-67) as a self-sacrificing template. After calcination it, the obtained CoMgAl-borate LDO can inherit the hollow hierarchical porous structure. Its unique structure has the merits of low density, large specific surface area, large pore size distribution and short diffusion pathway, which should be beneficial to the adsorption of larger dye molecules. The maximum uptake capacity of CoMgAl-borate LDO can even reach as high as 1493.3 mg g−1 for Congo red (CR) and 990.1 mg g−1 for methyl orange (MO) owing to the hierarchical hollow porous structure, the “memory effect”, electrostatic interactions, hydrogen bond and ion exchange between anionic dye and cationic adsorbent surface, surpassing those of most previously reported LDH-based adsorbents. The entire adsorption processes for CR and MO follow Langmuir isotherm and pseudo-second-order kinetics model. Moreover, the removal efficiency of CoMgAl-borate LDO can still reach 86.5% for CR and 84.3% for MO after recycling five times, indicating that CoMgAl-borate LDO is a very promising high-efficiency adsorbent. This work not only demonstrates that CoMgAl-borate LDO is a very green and efficient adsorbent for the removal of anionic dyes from wastewater, but also provides a strategy for the rational design and development of hollow nanostructures.