Ethylene Carbonate-diethyl Research Articles

In Situ XANES Analysis of Olivine-Type Cathode Materials to Study Kinetically Preferred State

Introduction Yao et al. invented "relaxation analysis" to make transition of electrode materials from kinetically preferred state to equilibrium state clear. Olivine-type cathode materials are included in it1-3. These materials are promising, having both large theoretical capacity and fine stability4. Previously, Park et al. found that the amount of LiFePO4 decreased and that of FePO4 increased at the relaxation process after the termination of lithium insertion by use of relaxation analysis2. They considered that the LiFePO4 including lithium defects preferable for Li diffusion formed during lithium insertion process and that the defective LiFePO4 separated to LiFePO4 without defects and FePO4 at the relaxation process. Synchrotron X-ray absorption near edge structure (XANES) method is a powerful tool to investigate the structural/electronic properties. XANES enable to measure the kinetically-preferred state directly during a reaction. In this study, we measured the in situ Fe K-edge XANES of LiFePO4 cathode during lithium insertion for the purpose of investigating the kinetically-preferred structure and comparing the result with that of relaxation analysis obtained by using the XRD-Rietveld method2. Experimental Cathode was prepared by mixing LiFePO4, carbon black, and polyvinylidenefluoride with a weight ratio of 70:15:15 in N-methlpyrrolidone solution. The slurry was spread onto aluminum foil current collector and dried in a 120°C vacuum oven. The cathode and lithium metal anode were separated by a polypropylene membrane separator. LiPF6 (1 M) in ethylene carbonate/diethyl carbonate (EC/DEC) (3:7 v/v) was used as the electrolyte. The 2032-type coin cell with X-Ray window was assembled in an argon-filled glove box. We first charged the cell to 4.0 V at a rate of 0.19 C and took 12 minutes for rest when the voltage got to 4.0 V. We subsequently discharged the cells at a rate of 0.32 C to 2.65 V. In situ Fe K-edge XANES measurement was performed in transmission mode at beamline 5S1 of Aichi Synchrotron Radiation Center. We took 3 minutes measurement and 1 minute interval per scan; the scan range was 150 eV before the Fe K absorption edge and 1000 eV after that. We merged three continuous patterns into one pattern to decrease noise and to improve the analysis precision. The composition x in Li(1-x)FePO4 of each merged pattern was calculated by integrating the current. We carried out a two-components analysis based on the linear combination of the last merged pattern, called Li-rich phase hereafter, and the merged pattern during the rest time before lithium insertion, called Li-lean phase hereafter, for either end by using Athena5program. Results and Discussion The composition of Li-lean phase and Li-rich phase were calculated as Li0.09FePO4 and Li0.85FePO4 respectively by using the integrating current. Figure 1 shows an example of two-components analysis for the composition of x = 0.28 in Li(1-x)FePO4 . The XANES pattern was well fitted with a low χ2value of 0.15%. It was found that the relative amount of Li-rich phase from two components analysis, 89.6%, was larger than the amount, 82.9%, calculated from the composition x in Li(1-x)FePO4. The large amount of Li-rich phase out of linear relationship may indicate that Li-rich phase with lithium defects formed in large amount during lithium insertion process. This is consistent with the result of the "Relaxation Analysis"2using the XRD-Rietveld method. [1] S. Park, M. Oda and T. Yao, Solid State Ionics 203(2011) 29-32.[2] S. Park, K. Kameyama and T. Yao, Electrochem. solid-state lett. 15(2012) A49-A52[3] Y. Satou, S. Komine, S. Park and T. Yao, Solid State Ionics, In Press[4] A. K. Padhi, K. S. Nanjundaswamy and J. B. Goodenough, J. Electrchem. Soc. 144(1997) 1188-1194[5] B. Ravel and M. Newville, J. Synchrotron Rad. 12(2005) 537-541

Concentrated electrolytes: decrypting electrolyte properties and reassessing Al corrosion mechanisms

Highly concentrated electrolytes containing carbonate solvents with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) have been investigated to determine the influence of eliminating bulk solvent (i.e., uncoordinated to a Li+ cation) on electrolyte properties. The phase behavior of ethylene carbonate (EC)–LiTFSI mixtures indicates that two crystalline solvates form—(EC)3:LiTFSI and (EC)1:LiTFSI. Crystal structures for these were determined to obtain insight into the ion and solvent coordination. Between these compositions, however, a crystallinity gap exists. A Raman spectroscopic analysis of the EC solvent bands for the 3–1 and 2–1 EC–LiTFSI liquid electrolytes indicates that ∼86 and 95%, respectively, of the solvent is coordinated to the Li+ cations. This extensive coordination results in significantly improved anodic oxidation and thermal stabilities as compared with more dilute (i.e., 1 M) electrolytes. Further, while dilute EC–LiTFSI electrolytes extensively corrode the Al current collector at high potential, the concentrated electrolytes do not. A new mechanism for electrolyte corrosion of Al in Li-ion batteries is proposed to explain this. Although the ionic conductivity of concentrated EC–LiTFSI electrolytes is somewhat low relative to the current state-of-the-art electrolyte formulations used in commercial Li-ion batteries, using an EC–diethyl carbonate (DEC) mixed solvent instead of pure EC markedly improves the conductivity.

Human hair-derived carbon flakes for electrochemical supercapacitors

Heteroatom doped porous carbon flakes were prepared via carbonization of Chinese human hair fibers and employed for high-performance supercapacitor electrode materials. The morphology and chemical composition of the resultant carbon materials were characterized by electron microscopy (EM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) measurements. Human hair carbonized at 800 °C exhibited high charge storage capacity with a specific capacitance of 340 F g−1 in 6 M KOH at a current density of 1 A g−1 and good stability over 20 000 cycles. The specific capacitance of 126 F g−1 is also verified in a 1 M LiPF6 ethylene carbonate/diethyl carbonate (EC/DEC) organic electrolyte at a current density of 1 A g−1. The high supercapacitor performance could be due to the micro/mesoporosity combined with high effective surface area and heteroatom doping effects, combining double layer and Faradaic contributions.

The Influence of PMS-Additive on the Electrode/Electrolyte Interfaces in LiFePO4/Graphite Li-Ion Batteries

The influence of a film-forming additive, propargyl methanesulfonate (PMS), on electrochemical performance and electrode/electrolyte interface composition of LiFePO4/graphite Li-ion batteries has been studied. Combined use of in-house X-ray photoelectron spectroscopy (XPS) and soft and hard X-ray photoelectron spectroscopy (PES) enabled nondestructive depth profiling at four different probing depths in the 2-50 nm range. Cells cycled with PMS and LiPF6 in ethylene carbonate/diethyl carbonate (EC/DEC) were compared to a reference sample cycled without PMS. In the first cycle, PMS cells showed a higher irreversible capacity, which is explained by formation of a thicker solid electrolyte interphase (SEI). After three cycles, the SET thicknesses were determined to be 19 and 25 nm for the reference and PMS samples, respectively. After the initial cycling, irreversible losses shown by the PMS cells were lower than those of the reference cell. This could be attributed to a different SET composition and lower differences in the amount of lithium between lithiated and delithiated electrodes for the PMS sample. It was suggested that PMS forms a triple-bonded radical on reduction, which further reacts with the electrolyte. The PMS additive was shown to influence the chemical composition at the positive electrode/electrolyte interface. Thicker interface layers with higher C-O and smaller LiF contributions were formed on LiFePO4 cycled with PMS.

Electrochemical characterisation of a lithium-ion battery electrolyte based on mixtures of carbonates with a ferrocene-functionalised imidazolium electroactive ionic liquid

Electrolytic solutions of lithium-ion batteries can be modified with additives to improve their stability and safety. Electroactive molecules can be used as such additives to act as an electron (redox) shuttle between the two electrodes to prevent overcharging. The electroactive ionic liquid, 1-ferrocenylmethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (TFSI), was synthesised and its electrochemical properties were investigated when diluted with ethylene carbonate-diethyl carbonate solvent at various concentrations. Cyclic voltammetry data were gathered to determine the redox potential, diffusion coefficient and heterogeneous rate constants of the electroactive imidazolium TFSI ionic liquid in the carbonate solution. The properties of this molecule as an additive in lithium battery electrolytes were studied in standard coin cells with a metallic Li anode and a Li4Ti5O12 cathode.

Effect of nano-clay on ionic conductivity and electrochemical properties of poly(vinylidene fluoride) based nanocomposite porous polymer membranes and their application as polymer electrolyte in lithium ion batteries

Hybrid organic–inorganic polymer gel electrolytes (PGEs) based on polymer–clay nanocomposite microporous membrane containing 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate/diethyl carbonate (EC/DEC) are fabricated and their electrochemical characteristics in lithium ion batteries are studied. Poly(vinylidene fluoride) (PVdF)–clay nanocomposite membrane containing different clay loading are prepared by phase inversion method. Aqueous suspension of montmorrillonite (MMT) clay in dimethyl acetamide (DMAc) is used as the nano-clay. The morphology of the clay dispersion with sonication time is studied by environmental scanning electron microscope (E-SEM). The intercalation/exfoliation of polymer–clay nanocomposite is characterized by X-ray diffraction (XRD). Differential scanning calorimetry (DSC) and thermal gravimetric analysis are used for the evaluation of thermal properties. DSC analysis shows that crystallinity of nanocomposite decreases with increasing nano-clay content. The effect of clay on the membrane morphology, ionic conductivity and electrochemical properties of the PGEs in lithium ion rechargeable batteries are studied and results are compared. Incorporation of 2wt.% nano-clay in PGE enhances its ionic conductivity from 0.78 to 3.08mScm−1 at room temperature. Li-ion half cell comprising of Li/PVdF–clay(2wt.%)-PGE/LiMn2O4 delivers high charge–discharge capacity (∼120mAhg−1) and shows stable cycle performance.

Temperature Dependence of Self-Diffusion Coefficients of Ions and Solvents in Ethylene Carbonate, Propylene Carbonate, and Diethyl Carbonate Single Solutions and Ethylene Carbonate + Diethyl Carbonate Binary Solutions of LiPF6 Studied by NMR

The self-diffusion coefficients, D, of lithium, anions, and solvents in four binary-solution electrolytes of ethylene carbonate (EC)–diethyl carbonate (DEC) and three single-solution electrolytes of EC, DEC, and propylene carbonate (PC) including 1 M LiPF6 were measured by 1H, 7Li, and 19F NMR spectroscopy from (353 to 243) K or above freezing for seven solution electrolytes. In the single DEC electrolyte, DLi and DPF6 had almost the same values at every temperature, whereas DLi was smaller than DPF6 in the EC and PC solutions. In the binary EC–DEC electrolytes, as the ratio of EC increased, DLi gradually became smaller, while DPF6 remained almost unchanged in the temperature range studied. At 303 K, the degree of ion dissociation α was evaluated from the ionic conductivity, DLi and DPF6. The α value increased from 0.17 to 0.71 as the EC ratio increased from (0 to 100) %.

Salt Diffusion Coefficients, Concentration Dependence of Cell Potentials, and Transference Numbers of Lithium Difluoromono(oxalato)borate-Based Solutions

Several properties of the electrolyte solution lithium difluoromono(oxalato)borate (LiDFOB) in ethylene carbonate diethylcarbonate (EC/DEC (3:7 mass ratio)) are given, including transference numbers, diffusion coefficients, concentration dependence of cell potentials, and the Haven ratio. The concentration range of the salt covers 0.1 mol·kg–1 to 1.0 mol·kg–1. In comparison to the standard salt LiPF6 currently in use in lithium ion cells LiDFOB has higher transference numbers. However, the Haven ratio related to ion pair formation in an electrolyte indicates a high amount of aggregates in concentrated LiDFOB/EC/DEC (3:7) electrolytes.

Development of Acoustic Emission Clustering Method to Detect Degradation of Lithium Ion Batteries

Lithium ion batteries are widely used for electrical devices. However, their degradation causes serious accidents such as fires or explosions. In order to detect the degradation of a lithium ion battery during charging and discharging in real time, an acoustic emission (AE) technique was applied and a clustering method was developed to extract AE signals caused by battery degradation. In this study, highly oriented pyrolytic graphite (HOPG) and a lithium metal were used as working and counter electrodes, respectively, and a glass fiber sheet was used as a separator. An ethylene carbonate / diethyl carbonate (EC/DEC) solution, which was used as the electrolyte solution, was sealed in a metallic shell. Degradation of this type of battery mainly occurred by gas evolution and fracture or exfoliation of the graphite electrode. During the first charging and discharging cycle, 499 AE signals were detected. AE signals were clustered by a method that was developed based on the waveform polarity, power spectrum, and enveloped waveform. These features were first clustered by correlation coefficients. AE signals which the Euclidean distance of each feature was close were clustered into the same cluster. AE signals were clustered into 43 clusters by this method. In order to characterize clustered AE signals from a degrading battery, the clustered signals were compared to artificial AE signals created by simulating degradation behavior in the battery. Gas evolution on an electrode in the battery was simulated by electrolysis of water. AE signals due to graphite fracture were simulated by mechanically fracturing the graphite in a Vickers indentation test. As a result, AE signals characterizing gas evolution were detected continuously during the cycle. This result constituted gas evolution phenomena in the battery. Fracture-related AE signals due to graphite electrode exfoliation tended to occur when the lithium intercalation rate changed. Thus, fracture or exfoliation of graphite was attributed to the formation of a solid electrolyte interface (SEI) or volume expansion/contraction due to lithium intercalation, respectively. Other classes AE signals were also discussed, of which some were attributed to the distortion of graphite.

Ionomer Binders Can Improve Discharge Rate Capability in Lithium-Ion Battery Cathodes

A lithium-ion form of a perfluorosulfonate ionomer was used as a binder in -based lithium-ion battery cathodes. Carbon-coated and acetylene carbon black were blended with ionomer to prepare composite cathodes having a composition 60% , 20% acetylene carbon black, and 20% binder by weight. Cathodes were tested against anodes using and –ethylene carbonate/diethyl carbonate (EC/DEC) electrolytes. Comparison was made with cathodes prepared using poly(vinylidene) difluoride (PVDF) as binder. At low discharge rates (e.g., C/5) both cathode types exhibited similar charge–discharge capacities and voltage profiles. However, under higher rate discharge conditions (e.g., , up to 5C) cathodes prepared using ionomer binder showed better discharge rate capability than cathodes having PVDF binder. This phenomenon was more pronounced when the salt concentration in the electrolyte was low (e.g., ). These findings suggest that use of ionic binders can help to compensate for electrolyte depletion from the electrode porous space as lithium ions are intercalated into lithium-deficient particles during rapid discharging. Potential uses for electrodes having ionomer binders in enabling lower cost battery electrolytes (because of the reduced need for salt) and in developing high rate cathodes that are nonporous or have low porosity are discussed.

Dynamics of lithium electrode passivation in aprotic organic electrolytes, studied by electrochemical noise method

Lithium electrode passivation is studied in different organic electrolytes, namely, 1 M LiClO4 in 1,3-dioxolane, 1 M LiN(CF3SO2)2 in 1,3-dioxolane, 1 M LiPF6 in an ethylene carbonate-diethyl carbonate mixture, 1 M LiPF6 in an ethylene carbonate-dimethyl carbonate mixture, using the electrochemical noise method. The dynamics of passive film formation on the lithium surface in the mentioned electrolytes that differ in their corrosivity towards lithium is followed.

Compatibility of quaternary ammonium-based ionic liquid electrolytes with electrodes in lithium ion batteries

Electrochemical intercalation/deintercalation behavior of lithium into/from electrodes of lithium ion batteries was comparatively investigated in 1 mol/L LiClO 4 ethylene carbonate–diethyl carbonate (EC-DEC) electrolyte and a quaternary ammonium-based ionic liquid electrolyte. The natural graphite anode exhibited satisfactory electrochemical performance in the ionic liquid electrolyte containing 20 vol.% chloroethylenene carbonate (Cl-EC). This is attributed to the mild reduction of solvated Cl-EC molecules at the graphite/ionic electrolyte interface resulting in the formation of a thin and homogenous SEI on the graphite surface. However, rate capability of the graphite anode is poor due to the higher interfacial resistance than that obtained in 1 mol/L LiClO 4/EC-DEC organic electrolyte. Spinel LiMn 2O 4 cathode was also electrochemically cycled in the ionic electrolyte showing satisfactory capacity and reversibility. The ionic electrolyte system is thus promising for 4 V lithium ion batteries based on the concept of “greenness and safety”.

Comparison of the Reaction of Li[sub x]Si or Li[sub 0.81]C[sub 6] with 1 M LiPF[sub 6] EC:DEC Electrolyte at High Temperature

The reaction of lithiated silicon (Li x Si) with 1 M LiPF 6 ethylene carbonate-diethyl carbonate(EC:DEC) electrolyte was compared with that of Li 0.81 C 6 and the same electrolyte using accelerating rate calorimetry (ARC). In the presence of LiPF 6 -containing electrolyte, Li x Si and Li 0.81 C 6 showed similar ARC response in cases where the same number of moles of lithium atoms and the same amount of electrolyte were involved. X-ray diffraction results indicate that the major reaction product is comprised primarily of LiF for both Li x Si and Li 0.81 C 6 . Apparently, the LiF reaction product reduces the reactivity with electrolyte of both Li x Si and Li 0.81 C 6 . The self-heating rate of Li x Si reacting with electrolyte was less than that of Li 0.81 C 6 even though the specific surface area was about twice as large. This suggests composite electrodes using powdered Si-based electrode materials will be as safe as or safer than corresponding graphite electrodes in full-scale Li-ion cells. The reason that the lithiated silicon is safer than Li 0.81 C 6 is because silicon stores more Li per unit volume than graphite, leading to thicker LiF surface layers that slow the reaction with electrolyte.

Impact of Sodium Salt Coating on a Graphite Negative Electrode for Lithium-Ion Batteries

The electrochemical performance of a graphite electrode for rechargeable lithium-ion batteries was successfully enhanced by pretreatment of graphite powders with NaCl and Na 2 CO 3 aqueous solutions. The procedure of the pretreatment is simple and easy, that is, graphite powders are dispersed in the aqueous solutions, and then filtered and dried. Since the surface of the graphite powder was modified with a sodium salt coating, the irreversible capacity at the initial cycle was suppressed by the pretreatment which is capable of modifying the solid electrolyte interface layer formed on the graphite electrode. Further, reversible discharge capacities at 175 mA g -1 (C/2 rate when 350 mAh g -1 ) increased with better capacity retention in a 1 mol dm -3 LiClO 4 ethylene carbonate-diethyl carbonate electrolyte solution.

Potassium Salts

Electrochemical performance of a natural graphite anode was successfully enhanced by the addition of three different potassium salts into 1 mol/dm 3 LiClO 4 ethylene carbonate-diethyl carbonate electrolyte. The presence of K salts in the electrolyte prior to the charge-discharge cycle considerably reduced the irreversible capacity loss at the first cycle. The reversible capacity and rate capability of the graphite anode were also improved. The electrochemical enhancement of the natural graphite anode was attributed to the mild electrolyte reduction reaction at the electrode/electrolyte interface resulting in the formation of a thin, homogenous, and more conductive solid electrolyte interface on the graphite surface.

Comparison of the Reactions Between Li7 / 3Ti5 / 3 O 4 or LiC6 and Nonaqueous Solvents or Electrolytes Using Accelerating Rate Calorimetry

The reactions of discharged or discharged mesocarbon microbead with ethylene carbonate/diethyl carbonate (EC/DEC) (1:2 by volume) solvent, 1 M EC/DEC or 0.8 M LiBOB EC/DEC are compared using accelerating rate calorimetry (ARC). We find that (1.5 V vs. Li) shows lower reactivity than (0.05 V vs. Li) in EC/DEC solvent or in -based electrolyte. The reactions between both electrodes and 1 M EC/DEC proceed in a clear stepwise fashion, where first, intercalated lithium reacts with (from the decomposition of to produce LiF, and then, when the is consumed, the remaining lithium reacts with the solvents. The addition of 0.8 M LiBOB to EC/DEC solvent greatly increases the thermal stability of both and X-ray diffraction (XRD) studies show that both and react with EC/DEC or LiBOB EC/DEC to produce at the end of the ARC experiments. XRD studies show that reacts with 1 M EC/DEC to form LiF, and some In fact, even a fresh sample of reacts with 1 M EC/DEC to produce substantial quantities of and LiF, but little heat is evolved during this reaction since the Li in is so tightly bound. The results in this paper suggest that safer lithium-ion cells could be built using negative electrodes than with graphite negative electrodes. © 2004 The Electrochemical Society. All rights reserved.

Thermal Stability of 18650 Size Li-Ion Cells Containing LiBOB Electrolyte Salt

Lithium bis(oxalato)borate (LiBOB) has been proposed recently as an electrolyte salt for Li-ion batteries, however safety testing of full Li-ion cells incorporating this salt has not been reported. Earlier accelerating rate calorimetry (ARC) work demonstrated that the thermal reactivity between LiBOB ethylene carbonate/diethyl carbonate (EC/DEC) electrolyte and was lower than that between EC/DEC electrolyte and the same negative electrode material, suggesting that LiBOB may be an attractive salt choice for safer Li-ion cells. Here, we report ARC studies of the reactions between LiBOB EC/DEC electrolyte and and compare them to the reactions between EC/DEC and the same positive electrode material. Unfortunately, the reactivity of LiBOB electrolyte with the charged positive electrode initiates at a substantial rate at about 40°C lower in temperature than for electrolyte. Oven exposure tests on charged (4.2 V) 18650 Li-ion cells made using the same electrolytes and electrode materials show that the heat caused by the reaction of the negative electrode with electrolyte is less for LiBOB electrolyte than for electrolyte but that the opposite is true for the heat caused by the reaction of the positive electrode with electrolyte, as expected based on the ARC measurements. Using ARC tests on the individual electrode reactivity and oven exposure testing on 18650 Li-ion cells, the usefulness of electrolytes with mixed salts is also explored. © 2004 The Electrochemical Society. All rights reserved.

Tin Alloy-Graphite Composite Anode for Lithium-Ion Batteries

A composite anode material was prepared that contains nanosize (<100 nm) particles of tin alloy and The alloys were electroplated at high current densities (above from aqueous solutions, directly onto the copper current collector, and were coated by a polyvinylidene fluoride-graphite matrix at a ratio of alloy:graphite matrix 70:30 and 80:20 w/w, respectively. The processes involved in electrode production by this method are inexpensive, simple, and fast. Over 40 (100% depth of discharge) cycles were demonstrated, in half-cell, and over 30 were demonstrated with a battery containing 1 M ethylene carbonate-diethyl carbonate electrolyte. The faradaic efficiency is less than 100%. Lithium is fully deinserted from the host matrix only when the anode is cycled at low current densities. The kinetics of lithium insertion to and deinsertion from the composite anode material, slow gradually as the cycle number increases. X-ray diffraction patterns of the anode material show that the alloy becomes amorphous during cycling, while the graphite does not. X-ray photoelectron-spectroscopy measurements reveal that the solid electrolyte interphase consists of mainly LiF, small amounts of and possibly, polymeric substances. The electrochemical behavior of the alloy changes with cycle number, while that of the graphite does not. The fall of the deinsertion capacity of the graphite from the first cycle to the 34th by more than 50% proves that the active material in the anode suffers from particle-to-particle break off. © 2002 The Electrochemical Society. All rights reserved.

Performance of Li-ion cells with new electrolytes conceived for low-temperature applications

In an effort to develop a useful electrolyte for a Li-ion cell applicable in a wide operation temperature, we have studied a number of ternary electrolytes containing a cyclic carbonate (ethylene carbonate (EC)), a linear carbonate (dimethyl carbonate (DMC), diethyl carbonate (DEC), or ethylmethyl carbonate (EMC)), and a low-temperature freezing solvent (methyl acetate, ethyl acetate, isopropyl acetate, isoamyl acetate, or ethyl propionate (EP)). We have studied performance including cycle life of Li-ion cells containing these electrolytes at various temperatures. The performance was various with various electrolyte compositions showing a significant effect of the low-temperature freezing solvents while the effect of the linear carbonates was relatively minor. Cells containing an electrolyte of EC–DMC–MA showed an excellent initial performance at −20°C but it did not give a good cycle life compared with others. Two electrolyte compositions containing EP, EC–DEC–EP and EC–EMC–EP, showed the most attractive overall performance including initial performance at −20°C, cycle life and rate capability at room temperature as well as 50°C.

Effect of organic additives in electrolyte solutions on lithium electrode behavior

Charge–discharge behavior of Li and Li–Al anodes has been investigated by measurement of AC impedance and polarization resistance. The anodes showed lower interfacial resistance in ethylene carbonate (EC)–dimethyl carbonate (DMC)/1 M LiPF6 than that in EC–diethyl carbonate (DEC)/1 M LiPF6. The interfacial resistance between Li–Al electrode and electrolyte solution decreased with content of Al in the alloy. Further, addition of 2-methylfuran (2MeF), 2-methyltetrahydrofuran (2MeTHF), 2-methylthiophene (2MeTp) and polyethylene oxide (PEO) in the electrolyte solutions decreased the polarization resistance.