Non-flammable long chain phosphate ester based electrolyte via competitive solventized structures for high-performance lithium metal batteries

Safety remains a persistent challenge for high-energy-density lithium metal batteries(LMBs).The development of safe and non-flammable electrolytes is especially important in harsh conditions such as high temperatures.Herein,a flame-retardant,low-cost and thermally stable long chain phosphate ester based(tributyl phosphate,TBP)electrolyte is reported,which can effectively enhance the cycling stability of highly loaded high-nickel LMBs with high safety through co-solvation strategy.The interfacial compatibility between TBP and electrode is effectively improved using a short-chain ether(glycol dimethyl ether,DME),and a specially competitive solvation structure is further constructed using lithium borate difluorooxalate(LiDFOB)to form the stable and inorganic-rich electrode interphases.Benefiting from the presence of the cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)enriched with LiF and Li_(x)PO_(y)F_(z),the electrolyte demonstrates excellent cycling stability assembled using a 50μm lithium foil anode in combination with a high loading NMC811(15.4 mg cm^(-2))cathode,with 88%capacity retention after 120 cycles.Furthermore,the electrolyte exhibits excellent high-temperature characteristics when used in a 1-Ah pouch cell(N/P=0.26),and higher thermal runaway temperature(238℃)in the ARC(accelerating rate calorimeter)demonstrating high safety.This novel electrolyte adopts long-chain phosphate as the main solvent for the first time,and would provide a new idea for the development of extremely high safety and high-temperature electrolytes.

Theoretical analysis of hydrogen solubility in direct coal liquefaction solvents

The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.

Coordination structure regulation in non-flammable electrolyte enabling high voltage lithium electrochemistry

High-voltage battery systems bring significant increases in energy density but are also accompanied by fast degradation of electrochemical performance and serious safety issues.Herein,Li^(+)coordination structure regulation was conducted to formulate a non-flammable electrolyte,which consists of 1.5 M lithium bis(fluor sulfonyl)imide(LiFSI)in triethyl phosphate and methyl 2,2,2-trifluoromethyl carbonate(FEMC).The renamed TEP-FEMC-FEC(TFF)electrolyte exhibits an FSI^(−)-dominated solvation structure contributed by the weakly-solvating ability of FEMC.The generated inorganic-rich interfacial layers are conducive to stabilizing the phase transition of high-voltage cathodes while suppressing the dendritic growth on lithium metal or co-intercalation behavior in graphite anode.This TFF electrolyte enables LiCoO_(2)||Li batteries to achieve capacity maintenance over 79%after 400 cycles with high-rate of 5 C at an ultra-high voltage of 4.6 V,and an outstanding capacity exceeding 100 mA h g^(−1)even at a super-high current density of 20 C.Additionally,the Ah-level LiCoO_(2)||graphite pouch cells also exhibit high capacity retention and satisfactory safety performance even under fast charging.This work provides a novel research direction for the pursuit of high energy density non-flammable electrolytes.

Low-melting mixture solvents:extension of deep eutectic solvents and ionic liquids for broadening green solvents and green chemistry

Green solvents such as water and ionic liquids(ILs)are pillars of the great mansion of green chemistry and green processing.Initially proposed as a new family of ILs,deep eutectic solvents(DESs)have received fast development in the past two decades.In this contribution,DESs are reviewed critically and the concept is extended to lowmelting mixture solvents(Lo MMSs),which cover all kinds of materials including ionic compounds,molecular compounds,and metals.Six classes of Lo MMSs are proposed as the new classification system and examples are given.Finally,several thermodynamic issues concerning Lo MMSs are discussed.Two new concepts,robustness of Lo MMSs and high-entropy Lo MMSs,are proposed.

Insight into the experiment and extraction mechanism for separating carbazole from anthracene oil with quaternary ammonium-based deep eutectic solvents

Carbazole is an irreplaceable basic organic chemical raw material and intermediate in industry.The separation of carbazole from anthracene oil by environmental benign solvents is important but still a challenge in chemical engineering.Deep eutectic solvents (DESs) as a sustainable green separation solvent have been proposed for the separation of carbazole from model anthracene oil.In this research,three quaternary ammonium-based DESs were prepared using ethylene glycol (EG) as hydrogen bond donor and tetrabutylammonium chloride (TBAC),tetrabutylammonium bromide or choline chloride as hydrogen bond acceptors.To explore their extraction performance of carbazole,the conductor-like screening model for real solvents (COSMO-RS) model was used to predict the activity coefficient at infinite dilution (γ^(∞)) of carbazole in DESs,and the result indicated TBAC:EG (1:2) had the stronger extraction ability for carbazole due to the higher capacity at infinite dilution (C^(∞)) value.Then,the separation performance of these three DESs was evaluated by experiments,and the experimental results were in good agreement with the COSMO-RS prediction results.The TBAC:EG (1:2) was determined as the most promising solvent.Additionally,the extraction conditions of TBAC:EG (1:2) were optimized,and the extraction efficiency,distribution coefficient and selectivity of carbazole could reach up to 85.74%,30.18 and 66.10%,respectively.Moreover,the TBAC:EG (1:2) could be recycled by using environmentally friendly water as antisolvent.In addition,the separation performance of TBAC:EG (1:2) was also evaluated by real crude anthracene,the carbazole was obtained with purity and yield of 85.32%,60.27%,respectively.Lastly,the extraction mechanism was elucidated byσ-profiles and interaction energy analysis.Theoretical calculation results showed that the main driving force for the extraction process was the hydrogen bonding ((N–H...Cl) and van der Waals interactions (C–H...O and C–H...π),which corresponding to the blue and green isosurfaces in IGMH analysis.This work presented a novel method for separating carbazole from crude anthracene oil,and will provide an important reference for the separation of other high value-added products from coal tar.

Reviewing electrochemical stability of ionic liquids-/deep eutectic solvents-based electrolytes in lithium-ion,lithium-metal and post-lithium-ion batteries for green and safe energy

Sustainable energy is the key issue for the environment protection,human activity and economic development.Ionic liquids(ILs)and deep eutectic solvents(DESs)are dogmatically regarded as green and sustainable electrolytes in lithium-ion,lithium-metal(e.g.,lithium-sulphur,lithium-oxygen)and post-lithium-ion(e.g.,sodium-ion,magnesium-ion,and aluminum-ion)batteries.High electrochemical stability of ILs/DESs is one of the prerequisites for green,sustainable and safe energy;while easy electrochemical decomposition of ILs/DESs would be contradictory to the concept of green chemistry by adding the cost,releasing volatile/hazardous by-products and hindering the recyclability.However,(1)are ILs/DESs-based electrolytes really electrochemically stable when they are not used in batteries?(2)are ILs/DESs-based electrolytes really electrochemically stable in real batteries?(3)how to design ILs/DESs-based electrolytes with high electrochemical stability for batteries to achieve sustainability and green development?Up to now,there is no summary on this topic,to the best of our knowledge.Here,we review the effect of chemical structure and non-structural factors on the electrochemical stability of ILs/DESs in simulated conditions.More importantly,electrochemical stability of ILs/DESs in real lithium-ion,lithium-metal and post-lithium-ion batteries is concluded and compared.Finally,the strategies to improve the electrochemical stability of ILs/DESs in lithium-ion,lithium-metal and post-lithium-ion batteries are proposed.This review would provide a guide to design ILs/DESs with high electrochemical stability for lithium-ion,lithium-metal and postlithium-ion batteries to achieve sustainable and green energy.

Efficient and reversible separation of NH_(3) by deep eutectic solvents with multiple active sites and low viscosities

The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.

Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

Oxidative Desulfurization of Fuel Oil with H_(3)PO_(4)-based Deep Eutectic Solvents

A series of Lewis-acid deep eutectic solvents (DESs) were synthesized by stirring phosphoric acid and zincchloride as raw materials at 80℃ to form H_(3)PO_(4)/nZnCl_(2) (n = 0.1, 0.25, 0.5, 0.75, 1). The DESs were characterized byFourier transform infrared spectrophotometry (FT-IR), thermogravimetry/differential thermogravimetry (TG/DTG), andelectron spray ionization mass spectrometry (ESI-MS). The DESs were used as both extractants and catalysts to removedibenzothiophene from fuels via oxidative desulfurization (ODS). Experiments were performed to investigated the influenceof factors such as composition of DES, temperature, oxidant dosage (molar ratio of O:S), DES dosage (volume ratio ofDES:oil), and number of cycles on desulfurization rate. The results indicated that the removal rate of dibenzothiophene (DBT)was affected by the Lewis acidic DESs, with that of H_(3)PO_(4)/0.25∙ZnCl_(2) reaching 96.4% under optimal conditions (Voil=5 mL,VDES=1 mL, an oxidant dosage of 6, T=50 ℃). After six cycles, the desulfurization rate of H_(3)PO_(4)/0.25∙ZnCl_(2) remained above94.1%. The apparent activation energy of dibenzothiophene (DBT) removal reaction was determined by a pseudo-first orderkinetic equation according to the Arrhenius equation to be 32.34 kJ/mol, as estimated. A reaction mechanism is proposedbased on the experimental data and characterization results.

Machine-Learning-Assisted Design of Deep Eutectic Solvents Based on Uncovered Hydrogen Bond Patterns

Non-ionic deep eutectic solvents(DESs)are non-ionic designer solvents with various applications in catalysis,extraction,carbon capture,and pharmaceuticals.However,discovering new DES candidates is challenging due to a lack of efficient tools that accurately predict DES formation.The search for DES relies heavily on intuition or trial-and-error processes,leading to low success rates or missed opportunities.Recognizing that hydrogen bonds(HBs)play a central role in DES formation,we aim to identify HB features that distinguish DES from non-DES systems and use them to develop machine learning(ML)models to discover new DES systems.We first analyze the HB properties of 38 known DES and 111 known non-DES systems using their molecular dynamics(MD)simulation trajectories.The analysis reveals that DES systems have two unique features compared to non-DES systems:The DESs have①more imbalance between the numbers of the two intra-component HBs and②more and stronger inter-component HBs.Based on these results,we develop 30 ML models using ten algorithms and three types of HB-based descriptors.The model performance is first benchmarked using the average and minimal receiver operating characteristic(ROC)-area under the curve(AUC)values.We also analyze the importance of individual features in the models,and the results are consistent with the simulation-based statistical analysis.Finally,we validate the models using the experimental data of 34 systems.The extra trees forest model outperforms the other models in the validation,with an ROC-AUC of 0.88.Our work illustrates the importance of HBs in DES formation and shows the potential of ML in discovering new DESs.

Research Progress of Deep Eutectic Solvents in Extraction of Plant Flavonoids

As a new type of green solvents,deep eutectic solvents(DESs)have the advantages of strong extraction ability,designability,simple preparation,low price,recoverability and biodegradation,and show great application potential in the field of plant flavonoid extraction.In this paper,the definition,classification and preparation methods of DESs were introduced.The effects of DES composition,molar ratio of DES components,water content of DES systems,liquid-material ratio,extraction temperature,extraction time and extraction auxiliary techniques on the extraction yield of plant flavonoids were expounded.The recycling methods of DESs were summarized.Existing problems of DESs in the field of plant flavonoids extraction were pointed out,and further research direction and trend were analyzed and prospected.

Stoichiometry and Stability Constant Values for Copper (II) Chelates with Ethylene Diamine in Deep Eutectic Solvents (DES) (Ethaline) Solutions

In this study we used the deep eutectic solvents (ionic liquids) to investigate the reaction between copper (II) with ethylene diamine (en). Two of the existing methods for analyzing spectrophotometric measurements have been applied for establishing, the stoichiometry and whenever possible, the stability constants of the chelates formed. The method of continuous variations was necessary to determine first whether, the metal ion and the ligand ethylene diamine form one or more than one chelate, when more than one chelate formed, the results obtained depend on the wavelength and for meaningful conclusions the wavelengths were carefully selected. The empirical formulae of the chelates were further substantiated by the molar ratio method. The effect of time and temperature on the formation and stability of these chelates in solution is also studied. The stability constants, K1 and K2 for the copper (II) chelates were calculated, though reliable, and are comparable to literature values.

An overview of deep eutectic solvents:Alternative for organic electrolytes,aqueous systems&ionic liquids for electrochemical energy storage

As the demand for sustainable energy sources continues to rise,the need for efficient and reliable energy storage systems becomes crucial.In order to effectively store and distribute renewable energy,new and innovative solutions must be explored.This review examines the deep eutectic solvents(DESs)as a green,safe,and affordable solution for the electrochemical energy storage and conversion field,offering tremendous opportunities and a promising future.DESs are a class of environment-friendly solvents known for their low toxicity and unique properties,such as their good conductivity,high thermal stability,and nonflammability.This review explores the fundamentals,preparations,and various interactions that often predominate in the formation of DESs,the properties of DESs,and how DESs are better than traditional solvents involving cost-ineffective and unsafe organic electrolytes and ionic liquids as well as inefficient aqueous systems due to low energy density for electrochemical energy storage applications.Then,a particular focus is placed on the various electrochemical applications of DESs,including their role in the electrolytes in batteries/supercapacitors,electropolishing and electrodeposition of metals,synthesis of electrode materials,recycling of electrodes,and their potential for use in CO_(2)capture.The review concludes by exploring the challenges,research gaps,and future potential of DESs in electrochemical applications,providing a comprehensive overview,and highlighting key considerations for their design and use.

Efficient and selective extraction of sinomenine by deep eutectic solvents

Sinomenine is the main bio-active ingredient of Sinomenii Caulis and usually produced by solventextraction techniques. However, the extraction of sinomenine suffers from the lack of highly efficient and environmentally-benign solvents. In this work, deep eutectic solvents(DESs) based on fragrances were synthesized, hydrogen-bond donors(HBDs) and hydrogen-bond acceptors(HBAs) components of DESs were identified and their extraction ability for sinomenine was evaluated and the extraction conditions were optimized by single-factor and orthogonal design experiments. It was found that the hydrogen-bonding interaction between sinomenine and DESs was the main extraction driving force and there was no explicit relationship between the extraction ability and the hydrophobicity of the DESs. The DESs could be recycled and sinomenine could be recovered quantitatively via backextraction. High-purity sinomenine((95.0 ± 2.3)%) could be produced. These findings suggest that DESs are highly-effective solvents for the isolation of sinomenine and exhibit great potential for the extraction of other bio-active compounds.

Effect of solvents on the morphology and structure of barium titanate synthesized by a one-step hydrothermal method

Tetragonal barium titanate was synthesized from barium hydroxide octahydrate and titanium tetrachloride through a simple one-step hydrothermal method.The effect of different solvents on the crystal structure and morphology of barium titanate nanoparticles during the hy-drothermal process was investigated.Except for ethylene glycol/water solvent,impurity-free barium titanate was synthesized in pure water,methanol/water,ethanol/water,and isopropyl alcohol/water mixed solvents.Compared with other alcohols,ethanol promotes the formation of a tetragonal structure.In addition,characterization studies confirm that particles synthesized in methanol/water,ethanol/water,and isopropyl al-cohol/water mixed solvents are smaller in size than those synthesized in pure water.In the case of alcohol-containing solvents,the particle size decreases in the order of isopropanol,ethanol,and methanol.Among all the media used in this study,ethanol/water is considered the optimum reaction media for barium titanate with high tetragonality(defined as the ratio of two lattice parameters c and a,c/a=1.0088)and small aver-age particle size(82 nm),which indicates its great application potential in multilayer ceramic capacitors.

Enhancing effect of choline chloride-based deep eutectic solvents with polyols on the aqueous solubility of curcumin–insight from experiment and theoretical calculation

The development of green solvents for enhancing aqueous solubility of drug curcumin remains a challenge. This study explores the enhancing effect of deep eutectic solvents(DESs) on the aqueous solubility of curcumin(CUR) via experiment and theoretical calculation. Choline chloride-based DESs with polyols 1,2-propanediol(1,2-PDO), 1,3-propanediol, ethylene glycol, and glycerol as hydrogen bond donors were prepared and used as co-solvents. The CUR aqueous solubility increased with increasing the DESs content at temperature of 303.15-318.15 K, especially in aqueous ChCl/1,2-PDO(mole ratio 1:4) solutions. The positive apparent molar volume values and reduced density gradient analysis confirmed the existence of strong interactions between CUR and solvent. The van der Waals interactions and hydrogen bonding coexisted in DESs monomer retained the stability of DESs structure after introducing CUR. Moreover,the lower interaction energy of DESs…CUR system than that of the counterpart DESs further proved the strong interaction between CUR and DESs. The lowest interaction energy of ChCl/1,2-PDO…CUR system indicated that this system was the most stable and ChCl/1,2-PDO was promising for CUR dissolution.This work provides efficient solvents for utilizing curcumin, contributing to a deep insight into the interactions between DES and CUR at the molecular level, and the role of DESs on enhancing drugs solubility.

Effect of Temperature on Extraction of Castor Oil from Castor Seeds Using Potential Green Solvents

Extraction of castor oil from castor seeds was investigated using different green solvents which include d-limonene, p-cymene, α-pinene, ethanol, and furfural at the temperature range of (323 - 413) K. The Soxhlet extraction method was employed to investigate the effect of temperature at atmospheric pressure. The focus of the study was to investigate a potential green solvent that can produce the high yields compared to the traditional solvent (hexane). The results show that at the average time of 3 hours and 30 minutes, the castor oil yield for green solvents were ranked as furfural (47.13%) > ethanol (45.37%) > p-cymene (39.15%) > d-limonene (39.13%) > α-pinene (38.11%). These castor oil yields were obtained at optimum temperatures for each green solvent. The castor oil yields were compared to the yield of hexane (31.36%) at same average time. The green solvents were recovered by using simple distillation, except furfural which was difficult to be recovered.

Volumetric and ultrasonic properties of thiamine hydrochloride drug in aqueous solutions of choline-based deep eutectic solvents at different temperatures

Important efforts have been made over the past years to improve the drug acts,which leads to the discovery of novel drug preparations and delivery systems.The optimal design of such processes requires a molecular-level understanding of the interactions between drug molecules and biological membranes.The thermodynamic investigation provides deep and complete knowledge of interactions and the choice of appropriate and suitable production compounds in pharmaceutical fields.Particularly,the analysis of drugs+co-solvents in aqueous media is the central issue in many types of research because they exert their impact by interacting with biological membranes.This work is aimed to measure the density and speed of sound for the thiamine hydrochloride in water+deep eutectic solvents(DESs)mixtures(choline chloride/urea,choline chloride/ethylene glycol and choline chloride/glycerol)at temperature range(293.15-308.15)K.By correlation of the evaluated parameters in some standard relations,the partial molar parameters i.e.apparent molar volumes,Vφ,m,and apparent molar isentropic compression,κ_(s,φ,m),are calculated.In addition,apparent molar isobaric expansion,E^(0)_(φ,m),and Hepler’s constant are computed from the density and speed of sound data.For fitting the experimental Vφ,m andκ_(s,φ,m)the Redlich-Meyer equation was employed that the important quantities;standard partial molar volume,V^(0)_(m),and partial molar isentropic compression,κφ,m0,were obtained.The thermodynamic analysis of the studied system also plays a crucial role in the pharmaceutical industry.

Intermolecular interactions induced property improvement for clean fracturing fluid by deep eutectic solvents

Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.

Solvents incubatedπ-πstacking in hole transport layer for perovskite-silicon 2-terminal tandem solar cells with 27.21%efficiency

Room temperature sputtered inorganic nickel oxide(NiO_(x))is one of the most promising hole transport layers(HTL)for perovskite-sillion 2-terminal tandem solar cells with the aid of ultrathin and compact organic layers to passivate the surface defects.In this study,the aromatic solvent with different substituent groups was used to regulate the conformation of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)am ine](PTAA)layer.As a result,the single-junction perovskite solar cell(PSC)gained a power conversion efficiency(PCE)of 20.63%,contributing to a 27.21%efficiency for monolithic perovskite/silicon(double-side polished)2-terminal tandem solar cell,by applying the alkyl aromatic solvent to enhance theπ-πstacking of PTAA molecular chains.The tandem solar cell can maintain 95%initial efficiency after aging over 1000 h.This study provides a universal approach for improving the photovoltaic performance of NiO_(x)/polymer-based perovskite/silicon tandem solar cells and other single junction inverted PSCs.