Thermal Conductivity of Ionic Liquids: Measurement and Prediction

This study reports thermal-conductivity data for a series of [EMIM] (1-ethyl-3-methylimidazolium)-based ionic liquids (ILs) having the anions [NTf₂] (bis(trifluoromethylsulfonyl)imide), [OAc] (acetate), [N(CN)₂] (dicyanimide), [C(CN)₃] (tricyanomethide), [MeOHPO₂] (methylphosphonate), [EtSO₄] (ethylsulfate), or [OcSO₄] (octylsulfate), and in addition for ILs with the [NTf₂]-anion having the cations [HMIM] (1-hexyl-3-methylimidazolium), [OMA] (methyltrioctylammonium), or [BBIM] (1,3-dibutylimidazolium). Measurements were performed in the temperature range between (273.15 and 333.15) K by a stationary guarded parallel-plate instrument with a total measurement uncertainty of 3 % (k = 2). For all ILs, the temperature dependence of the thermal conductivity can well be represented by a linear equation. While for the [NTf₂]-based ILs, a slight increase of the thermal conductivity with increasing molar mass of the cation is found at a given temperature, the [EMIM]-based ILs show a pronounced, approximately linear decrease with increasing molar mass of the different probed anions. Based on the experimental data obtained in this study, a simple relationship between the thermal conductivity, molar mass, and density is proposed for the prediction of the thermal-conductivity data of ILs. For this, also densities were measured for [EMIM][OAc], [EMIM][C(CN)₃], and [HMIM][NTf₂]. The mean absolute percentage deviation of all thermal-conductivity data for ILs found in the literature from the proposed prediction is about 7 %. This result represents a convenient simplification in the acquisition of thermal conductivity information for the enormous amount of structurally different IL cation/anion combinations available.     

A Cobalt-Free Multi-Phase Nanocomposite as Near-Ideal Cathode of Intermediate-Temperature Solid Oxide Fuel Cells Developed by Smart Self-Assembly

An ideal solid oxide fuel cell (SOFC) cathode should meet multiple requirements, i.e., high activity for oxygen reduction reaction (ORR), good conductivity, favorable stability, and sound thermo-mechanical/chemical compatibility with electrolyte, while it is very challenging to achieve all these requirements based on a single-phase material. Herein, a cost-effective multi-phase nanocomposite, facilely synthesized through smart self-assembly at high temperature, is developed as a near-ideal cathode of intermediate-temperature SOFCs, showing high ORR activity (an area-specific resistance of ≈0.028 Ω cm² and a power output of 1208 mW cm⁻² at 650 °C), affordable conductivity (21.5 S cm⁻¹ at 650 °C), favorable stability (560 h operation in single cell), excellent chemical compatibility with Sm_0.2Ce_0.8O_1.9 electrolyte, and reduced thermal expansion coefficient (≈16.8 × 10⁻⁶ K⁻¹). Such a nanocomposite (Sr_0.9Ce_0.1Fe_0.8Ni_0.2O_3–δ) is composed of a single perovskite main phase (77.2 wt%), a Ruddlesden–Popper (RP) second phase (13.3 wt%), and surface-decorated NiO (5.8 wt%) and CeO₂ (3.7 wt%) minor phases. The RP phase promotes the oxygen bulk diffusion while NiO and CeO₂ nanoparticles facilitate the oxygen surface process and O²⁻ migration from the surface to the main phase, respectively. The strong interaction between four phases in nanodomain creates a synergistic effect, leading to the superior ORR activity.     

Solid extractants prepared with ionic liquids and their use for recovery of actinides from nitric acid solutions

Solid extractants were prepared by noncovalent immobilization of phosphonium ionic liquids (ILs) on various polymeric materials, including fibrous materials. These sorption materials can be used for recovering Pu from 0.5–5 M HNO₃. Immobilization of phosphorus-containing ligands on solid supports using phosphonium ILs yields a material recovering actinides from nitric acid solutions.     

Thioether crown complexes as templates for the assembly of extended polyiodide networks: synthesis and structures of {[M([16]aneS4)]2I}I11 (M = Pd,Pt), [Pd(cis-HO)2[14]aneS4)](I3)2, [Pd([9]aneS3)2](Ix)2 (x = 3, 5)

Pd(II) and Pt(II) complexes of [16]aneS₄ and Pd(II) complexes of cis-(HO)₂[14]aneS₄ and [9]aneS₃ have been used as templates for the self-assembly of polyiodide ions. The complexes {[M([16]aneS₄)]₂I}I₁₁ (M = Pd, Pt), [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂, [Pd([9]aneS₃)₂](I_x)₂ (x = 3, 5) have been synthesized and structurally characterized. In {[M([16]aneS₄)]₂I}I₁₁, the polyiodide network consists of fused 14-member polyanion rings made up of interacting “L”-shaped I₅⁻ and I⁻ units; binuclear [([16]aneS₄)M–I–M([16]aneS₄)]³⁺ complex cations featuring a highly unusual linear and symmetric M–I–M moiety are each surrounded by one of these 14-member polyiodide rings in a belt-like fashion. The structures of [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂ and [Pd([9]aneS₃)₂](I₃)₂ both feature tri-iodides as counter-anions. In [Pd(cis-(HO)₂[14]aneS₄)](I₃)₂, quite asymmetric I₃⁻ ions form sinusoidal infinite chains via head-to-tail I₃⁻⋯I₃⁻ interactions; these chains run along the (001) direction and are stacked along the (100) direction to form highly puckered anionic layers via I⋯I weak interactions that cross-link the chains. In [Pd([9]aneS₃)₂](I₃)₂, [Pd([9]aneS₃)₂]²⁺ cations are bridged on each side by pairs of symmetric I₃⁻ ions through long-range S⋯I contacts to form discrete infinite ribbons that run parallel to the a axis. By contrast, the structure of [Pd([9]aneS₃)₂](I₅)₂ consists of highly puckered polyanionic layers featuring fused 18-member polyiodide rings made up of I₅⁻ ions. Two of these layers related by an inversion center are stacked along the b axis and interact with each other to form large cavities within which the complex cations sit. In these complex arrays the cation can be regarded as a template around which polyanion networks can be structured. The solid state FT-Raman spectra of the reported polyiodides are discussed on the basis of their crystal structures.     

Thermal conductivity of liquid hydrogen filled foam

The effective thermal conductivities of silica aerogel foam [0.1(10)⁻³ kg m⁻³ nominal density] filled with liquid n-H₂, liquid n-D₂ and an equimolar mixture of liquid H₂D₂ were measured near 19.6 K. Our measured value of 97 mW m⁻¹ K⁻¹ for hydrogen filled foam is essentially the same as for the liquid alone. This result agrees with predictions for the thermal conductivity of porous systems which give a 2% enhancement in the effective thermal conductivity for this system relative to the liquid alone.     

Insights into Electrolytic Pre-Lithiation: A Thorough Analysis Using Silicon Thin Film Anodes

Pre-lithiation via electrolysis, herein defined as electrolytic pre-lithiation, using cost-efficient electrolytes based on lithium chloride (LiCl), is successfully demonstrated as a proof-of-concept for enabling lithium-ion battery full-cells with high silicon content negative electrodes. An electrolyte for pre-lithiation based on γ-butyrolactone and LiCl is optimized using boron-containing additives (lithium bis(oxalato)borate, lithium difluoro(oxalate)borate) and CO₂ with respect to the formation of a protective solid electrolyte interphase (SEI) on silicon thin films as model electrodes. Reversible lithiation in Si||Li metal cells is demonstrated with Coulombic efficiencies (C_Eff) of 95–96% for optimized electrolytes comparable to 1 m LiPF₆/EC:EMC 3:7. Formation of an effective SEI is shown by cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). electrolytic pre-lithiation experiments show that notable amounts of the gaseous product Cl₂ dissolve in the electrolyte leading to a self-discharge Cl₂/Cl⁻ shuttle mechanism between the electrodes lowering pre-lithiation efficiency and causing current collector corrosion. However, no significant degradation of the Si active material and the SEI due to contact with elemental chlorine is found by SEM, impedance, and XPS. In NCM111||Si full-cells, the capacity retention in the 100th cycle can be significantly increased from 54% to 78% by electrolytic pre-lithiation, compared to reference cells without pre-lithiation of Si.     

Superconducting Cuprates with Charge Reservoir Consisting of either Peroxide-type Oxygen or H2O

Two novel homologous series of superconductive M-m2(n-1)n copper oxides with the charge-reservoir block consisting of either peroxide-type oxygen [0 ^(Ba) 2(n-1)n phases] or water [H-m2(n-1)n phases] are reported. The former phases with T _c 's higher than 100 K are obtained in the Ba-Ca-Cu-O system from high-pressure synthesis under oxidizing conditions. When exposed to open air, the latter phases spontaneously form from the highly unstable 0 ^(Ba) 2(n-1)n phases due to incorporation of H ₂ O molecules into the structure when exposed to open air. Besides water, the phase change is believed to involve additional protons from a redox reaction between water and the highly oxidized copper/peroxide-type oxygen of the 0 ^(Ba) 2(n-1)n phases. Upon the phase change the 0 ^(Ba) 2(n-1)n phases are reduced considerably, as was also confirmed by wet-chemical redox analysis.     

Study on optical weak absorption of borate crystals

Borate crystal is an important type of nonlinear optical crystals used in frequency conversion in all-solid-state lasers. Especially, LiB₃O₅ (LBO), CsB₃O₅ (CBO) and CsLiB₆O₁₀ (CLBO) are the most advanced. Although these borate crystals are all constructed by the same anionic group-(B₃O₇)⁵⁻, they show different nonlinear optical properties. In this study, bulk weak absorption values of three borate crystals have been studied at 1064 nm by a photothermal common-path interferometer. The bulk weak absorption values of them along [1 0 0], [0 1 0] and [0 0 1] directions were obtained, respectively, to be approximately 17.5 ppm cm⁻¹, 15 ppm cm⁻¹ and 20 ppm cm⁻¹ (LBO); 80 ppm cm⁻¹, 100 ppm cm⁻¹ and 40 ppm cm⁻¹ (CBO); 600 ppm cm⁻¹, 600 ppm cm⁻¹ and 150 ppm cm⁻¹ (CLBO) at 1064 nm. The results showed an obvious discrepancy of the values of these crystals along three axis directions. A correlation between the bulk weak absorption property and crystal intrinsic structure was then discussed. It is found that the bulk weak absorption values strongly depend on the interstitial area surrounded by the B–O frames. The interstitial area is larger, the bulk weak absorption value is higher.     

IR study of Pb-Sr titanate borosilicate glasses

The infrared spectra (IR) of various glass compositions in the glass system, [(Pb _x Sr_1−x )O·TiO₂]-[2SiO₂·B₂O₃]-[BaO·K₂O]-[La₂O₃], were recorded over a continuous spectral range (400–4000 cm⁻¹) to study their structure systematically. IR spectrum of each glass composition shows a number of absorption bands. These bands are strongly influenced by the increasing substitution of SrO for PbO. Various bands shift with composition. Absorption peaks occur due to the vibrational mode of the borate network in these glasses. The vibrational modes of the borate network are seen to be mainly due to the asymmetric stretching relaxation of the B-O bond of trigonal BO₃ units. More splitting is observed in strontium-rich composition.     

Kinetics of thorium(IV) nitrate extraction at various temperatures from aqueous salt solutions with a composite material based on a polymeric support and trialkylmethylammonium nitrate

The phase diagrams of the ternary liquid systems (TLSs) saturated hydrocarbon (decane, dodecane, tetradecane, pentadecane) (1)-[Th(NO₃)₄(TBP)₂] (2)-tri-n-butyl phosphate (TBP) (3) at T = 298.15 K are presented in the mole fraction scale. The TLSs are characterized by the areas of homogeneous solutions and of two-phase liquid systems (systems with phase separation), with one of the phases (I) enriched in [Th(NO₃)₄·(TBP)₂] and TBP and the other phase (II), in the hydrocarbon diluent. Using the data on the mutual solubility in the binary systems [Th(NO₃)₄(TBP)₂]-saturated hydrocarbon and in TLSs and the equations of the NRTL model, the intermolecular interaction parameters and the excess Gibbs energies (G ^ex) for the binary and ternary liquid systems along the binodal curve were calculated. For the examined systems, G ^ex > 0 and decreases in the order of binary systems 1–2, 1–3, 2–3. For the binary systems [Th(NO₃)₄(TBP)₂]-CnH_2n+2, G ^ex decreases in the order pentadecane, tetradecane, dodecane, decane and for the binary systems TBP-CnH_2n+2 it only slightly depends on particular hydrocarbon. The behavior of the activity coefficients of the system components for the extraction isotherms of thorium(IV) nitrate with 30–100% solutions of TBP in pentadecane was considered.     

A Tandem Organic Solar Cell with PCE of 14.52% Employing Subcells with the Same Polymer Donor and Two Absorption Complementary Acceptors

The tandem structure is an efficient way to simultaneously tackle absorption and thermalization losses of the single junction solar cells. In this work, a high‐performance tandem organic solar cell (OSC) using two subcells with the same donor poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione))] (PBDB‐T) and two acceptors, F‐M and 2,9‐bis(2‐methylene‐(3(1,1‐dicyanomethylene)benz[f ]indanone))7,12‐dihydro‐(4,4,10,10‐tetrakis(4‐hexylphenyl)‐5,11‐diocthylthieno[3′,2′:4,5]cyclopenta[1,2‐b]thieno[2″,3″:3′,4′]cyclopenta[1′,2′:4,5]thieno[2,3‐f][1]benzothiophene (NNBDT), with complementary absorptions is demonstrated. The two subcells show high V_oc with value of 0.99 V for the front cell and 0.86 V for the rear cell, which is the prerequisite for obtaining high V_oc of their series‐connected tandem device. Although there is much absorption overlap for the subcells, a decent J_sc of the tandem cell is still obtained owing to the complementary absorption of the two acceptors in a wide range. With systematic device optimizations, a best power conversion efficiency of 14.52% is achieved for the tandem device, with a high V_oc of 1.82 V, a notable FF of 74.7%, and a decent J_sc of 10.68 mA cm^?2. This work demonstrates a promising strategy of fabricating high‐efficiency tandem OSCs through elaborate selection of the active layer materials in each subcell and tradeoff of the V_oc and J_sc of the tandem cells.     

A Novel Aqueous Asymmetric Supercapacitor based on Pyrene-4,5,9,10-Tetraone Functionalized Graphene as the Cathode and Annealed Ti3C2Tx MXene as the Anode

Asymmetric supercapacitors (ASCs), employing two dissimilar electrode materials with a large redox peak position difference as cathode and anode, have been designed to further broaden the voltage window and improve the energy density of supercapacitors. Organic molecule based electrodes can be constructed by combining redox-active organic molecules with conductive carbon-based materials such as graphene. Herein, pyrene-4,5,9,10-tetraone (PYT), a redox-active molecule with four carbonyl groups, exhibits a four-electron transfer process and can potentially deliver a high capacity. PYT is noncovalently combined with two different kinds of graphene (Graphenea [GN] and LayerOne [LO]) at different mass ratios. The PYT-functionalized GN electrode (PYT/GN 4–5) possesses a high capacity of 711 F g⁻¹ at 1 A g⁻¹ in 1 M H₂SO₄. To match with the PYT/GN 4–5 cathode, an annealed-Ti₃C₂T_x (A-Ti₃C₂T_x) MXene anode with a pseudocapacitive character is prepared by pyrolysis of pure Ti₃C₂T_x. The assembled PYT/GN 4–5//A-Ti₃C₂T_x ASC delivers an outstanding energy density of 18.4 Wh kg⁻¹ at a power density of 700 W kg⁻¹. The PYT-functionalized graphene holds great potential for high-performance energy storage devices.     

Flexible Co–Mo–N/Au Electrodes with a Hierarchical Nanoporous Architecture as Highly Efficient Electrocatalysts for Oxygen Evolution Reaction

Designing highly active and robust electrocatalysts for oxygen evolution reaction (OER) is crucial for many renewable energy storage and conversion devices. Here, self-supported monolithic hybrid electrodes that are composed of bimetallic cobalt–molybdenum nitride nanosheets vertically aligned on 3D and bicontinuous nanoporous gold (NP Au/CoMoN_x) are reported as highly efficient electrocatalysts to boost the sluggish reaction kinetics of water oxidation in alkaline media. By virtue of the constituent CoMoN_x nanosheets having large accessible CoMoO_x surface with remarkably enhanced electrocatalytic activity and the nanoporous Au skeleton facilitating electron transfer and mass transport, the NP Au/CoMoN_x electrode exhibits superior OER electrocatalysis in 1 m KOH, with low onset overpotential (166 mV) and Tafel slope (46 mV dec⁻¹). It only takes a low overpotential of 370 mV to reach ultrahigh current density of 1156 mA cm⁻², ≈140-fold higher than free CoMoN_x nanosheets. The electrocatalytic performance makes it an attractive candidate as the OER catalyst in the water electrolysis.     

Effect of ionic liquids on the electroluminescence of yellowish-green light-emitting electrochemical cells using bis(2-(2,4-difluorophenyl)pyridine)4,7-diphenyl-1,10-phenanthroline-iridium(III) hexafluorophosphate

A cationic iridium complex [Ir(dfppy)₂(dpphen)]PF₆, where dfppy is 2-(2,4-difluorophenyl)pyridine, dpphen is 4,7-diphenyl-1,10-phenanthroline and PF₆⁻ is hexafluorophosphate, has been synthesized and its photophysical and electrochemical properties were investigated. Light-emitting electrochemical cells (LECs) based on this complex were fabricated using air stable electrodes and emits yellowish-green light (533 nm) with Commission Internationale de L’Eclairage (CIE) coordinates of (0.35, 0.59) at 4 V. Effect of two different imidazolium based ionic liquids (ILs) viz, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF₆) and 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIMPF₆) on the active layer has been studied and the luminance and the current density of the devices were found to be enhanced with increasing ionic conductivities.     

Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

Low temperature phase barium borate was synthesized by hydrothermal method. XRD analysis confirms the formation of γ-BBO or hydrated barium polyborate (Ba₃B₆O₉(OH)₆) which crystallizes in monoclinic system in the P2/c space group. The molecular structure analysis shows the presence of dominant BO₄ unit and the hydrated nature of material. γ-BBO exhibits sharp absorption edge at 202 nm and highly transparency in the UV–Visible–NIR region. The peak at 347 nm in the emission spectrum is due to the presence of self-trapped exciton. The third order nonlinear optical properties and limiting behavior of low temperature barium borate in both pulsed and continuous wave regime were studied. The effective 2PA absorption coefficient of γ-BBO under ns pulse excitation is estimated to be 0.38 × 10⁻¹⁰ m/W. The nonlinear absorption coefficient, refractive index and optical susceptibility of the material in cw regime were found to be in the order of 10⁻⁵ m W⁻¹, 10⁻¹² m² W⁻¹, 10⁻⁶ esu respectively. In both regimes, low temperature phase barium borate exhibits better optical limiting properties than high temperature phase β-BBO.     

Realization of a 594 Wh kg−1 Lithium-Metal Battery Using a Lithium-Free V2O5 Cathode with Enhanced Performances by Nanoarchitecturing

To realize a high-energy lithium metal battery (LMB) using a high-capacity Li-free cathode, in this work, nanoplate-stacked V₂O₅ with dominantly exposed (010) facets and a relatively short [010] length is proposed to be used as a cathode. The V₂O₅ nanostructure can be fabricated via a modified hydrothermal method, including a Li⁺ crystallization inhibitor, followed by heat treatment. In particular, the enlargement of the favorable Li⁺ diffusion pathway in the [010] direction and the formation of a robust hierarchical nanoplate-stacked structure in the modified V₂O₅ improves the electrochemical kinetics and stability; as a result, the nanoplate-stacked V₂O₅ electrode exhibits a higher capacity and rate performance (258 mAh g⁻¹ at 50 mA g⁻¹ [0.17 C], 140 mAh g⁻¹ at 1 A g⁻¹ [3.4 C]) and cycling capability (79% capacity retention after 100 cycles at 0.5 C) compared to the previously reported V₂O₅ nanobelt electrode. Notably, the LMB composed of Li//nanoplate-stacked V₂O₅ full-cells shows high specific energy densities of 594.1 and 296.2 Wh kg⁻¹ at 0.1 and 1.0 C, respectively, and a high Coulombic efficiency of 99.6% during 50 cycles.     

Preparation and characterization of ionic liquid intercalation compounds into layered zirconium phosphates

In this work, immobilizing a series of ionic liquids (ILs) 1-alkyl-3-methylimidazolium chloride [C _n mim]Cl (n = 2, 4, 6, 8) on the layered zirconium phosphates were investigated. [C₄mim]Cl was used to explore in detail the factors affecting intercalation. By comparing several starting materials including α-zirconium phosphate (α-ZrP), γ-zirconium phosphate (γ-ZrP) and the corresponding alkylamine preintercalated composites, it was found that the α-ZrP · 2BA (i.e., preintercalated BA were arranged in a bilayer mode at the galleries of α-ZrP) was a suitable host for intercalating ILs. Intercalation was verified with X-ray diffraction (XRD), Raman, UV–Vis and other instrumental approaches. pH effect on immobilization was investigated. Other ionic liquids including [C _n mim]Cl (n = 2, 6, 8) intercalation compounds were prepared. Based on XRD data, the interlayer distances of the studied intercalation compounds were similar, suggesting that the ionic liquids were arranged in an approximately planar manner, as confirmed by molecular modeling.     

Synergistic Ionic Liquid in Hole Transport Layers for Highly Stable and Efficient Perovskite Solar Cells

Perovskite solar cells (PSCs) with n-i-p structures often utilize an organic 2,2′,7,7′-tetrakis (N, N-di-p-methoxyphenyl-amine) 9,9′-spirobifluorene (spiro-OMeTAD) along with additives of lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI) and tert-butylpyridine as the hole transporting layer (HTL). However, the HTL lacks stability in ambient air, and numerous defects are often present on the perovskite surface, which is not conducive to a stable and efficient PSC. Therefore, constructive strategies that simultaneously stabilize spiro-OMeTAD and passivate the perovskite surface are required. In this work, it is demonstrated that a novel ionic liquid of dimethylammonium bis(trifluoromethanesulfonyl)imide (DMATFSI) could act as a bifunctional HTL modulator in n-i-p PSCs. The addition of DMATFSI into spiro-OMeTAD can effectively stabilize the oxidized spiro-OMeTAD⁺ cation radicals through the formation of spiro-OMeTAD⁺TFSI⁻ because of the excellent charge delocalization of the conjugated CF₃SO₂⁻ moiety within TFSI⁻. In addition, DMA⁺ cations could move toward the perovskite from the HTL, resulting in the passivation of defects at the perovskite surface. Accordingly, a power conversion efficiency of 23.22% is achieved for PSCs with DMATFSI and LiTFSI co-doped spiro-OMeTAD. Moreover, benefiting from the improved ion migration barrier and hydrophobicity of the HTL, still retained nearly 80% of their initial power conversion efficiency after 36 days of exposure to ambient air.     

Electropolymerization in proton-functionalized anilinium salts/glycol deep eutectic solvents

Novel proton-functionalized solid anilinium salts (anilinium hydrochloride ([HANI]Cl) and anilinium nitrate ([HANI]NO₃)) are synthesized. Simply mixing proton-functionalized anilinium salt with glycol in appropriate ratios can get deep eutectic solvents (DESs) which are liquid at room temperature. DES system is a new type of ionic liquids (ILs) or IL analogs. Tests show that the resulting DES systems have higher conductivity and lower viscosity which are suitable for electropolymerization. The electropolymerization of aniline in novel liquid DES ([HANI]Cl/(CH₂OH)₂ and [HANI]NO₃/(CH₂OH)₂) without exogenous protons is first reported. The cyclic voltammograms (CVs) in neat DES show two pairs of redox peaks. Unlike in acidic aqueous solutions, the electropolymerization of aniline in the DES needs no exogenous protons. UV–Vis and FTIR analysis show that the conductive polyaniline (PANI) is obtained. Moreover, the specific capacitance of PANI from the [HANI]Cl/(CH₂OH)₂ system is ca. 341 F g^?1 and that from the [HANI]NO₃/(CH₂OH)₂ is ca. 492 F g^?1, which are superior to that of the PANI obtained in an acid medium. The SEM characterization indicates that the resulting PANI on ITO is cross-linked nanoporous polymer membrane, which is benefit for the capacitance performance of PANI.     

N-Heterocyclic Olefin Type Ionic Liquid with Innate Soft Lewis-Base Character as an Effective Additive for Hybrid Quasi-2D and 3D Perovskite Solar Cells

In optimizing perovskites with ionic liquid (IL), the comparative study on Lewis acid-base (LAB) and hydrogen-bonding (HB) interactions between IL and perovskite is lacking. Herein, methyl is substituted for hydrogen on 2-position of imidazolium ring of N-heterocyclic carbene (NHC) type IL IdH to weaken HB interactions, and the resulting N-heterocyclic olefin (NHO) type IL IdMe with softer Lewis base character is studied in both hybrid quasi-2D (Q-2D) and 3D perovskites. It is revealed that IdMe participates in constructing high-quality Q-2D perovskite (n = 4) and provides stronger passivation for 3D perovskite compared with IdH. Power conversion efficiency (PCE) of Q-2D PEA₂MA₃Pb₄I₁₃ perovskite solar cells (PVSCs) is boosted to 17.68% from 14.03%. PCE and device stability of 3D PVSCs enhances simultaneously. Both theoretical simulations and experimental results show that LAB interactions between NHO and Pb²⁺ take the primary optimization effects on perovskite. The success of engineering LAB interactions also offers inspiration to develop novel ILs for high-performance PVSCs.