Electrolyte composition and metal-ion battery employing the same

TECHNICAL FIELD

The disclosure relates to an electrolyte composition and a metal-ion battery employing the same.

BACKGROUND

The electrolyte composition used in some conventional metal-ion batteries may include ionic liquid. Some aluminum-ion batteries employ an electrolyte composition that includes aluminum chloride and imidazolium chloride. The conventional electrolyte composition, which employs aluminum chloride and imidazolium chloride, exhibits good electrochemical reversibility and can be used in an aluminum-ion battery to stably execute the charging and discharging cycles. However, after numerous charging and discharging cycles, the metal material on the surface of the negative electrode in the battery grows in a specific direction. This is due to the numerous depositions and dissolutions, and can result in a dendritic growth on the negative surface. In additional, the self-corrosion effect of the negative electrode is caused by contact with the ionic liquid. The consumption of the aluminum negative electrode is increased, resulting in cycling instability and a short lifespan of the battery.

Therefore, the industry needs a novel electrolyte composition to overcome the problems mentioned above.

SUMMARY

According to embodiments of the disclosure, the disclosure provides a metal-ion battery. The metal-ion battery can include a positive electrode, a separator, a negative electrode, and the aforementioned electrolyte composition. The negative electrode can be separated from the positive electrode by the separator, and the electrolyte composition can be disposed between the positive electrode and the negative electrode.

DETAILED DESCRIPTION

The electrolyte composition and metal-ion battery of the disclosure are described in detail in the following description. In the following detailed description, for purposes of explanation, numerous specific details and embodiments are set forth in order to provide a thorough understanding of the present disclosure. The specific elements and configurations described in the following detailed description are set forth in order to clearly describe the present disclosure. It will be apparent, however, that the exemplary embodiments set forth herein are used merely for the purpose of illustration, and the inventive concept may be embodied in various forms without being limited to those exemplary embodiments. In the drawings, the size, shape, or thickness of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The disclosure will be described with respect to particular embodiments and with reference to certain drawings but the disclosure is not limited thereto.

The disclosure provides an electrolyte composition and a metal-ion battery employing the same. According to embodiments of the disclosure, besides a metal salt and an ionic liquid, the electrolyte composition of the disclosure further includes an additive with a specific structure. By means of the addition of the additive, during the charging/discharging of the battery (such as aluminum-ion battery), the electric field uniformity of the surface of the metal electrode (such as the aluminum electrode of the aluminum-ion battery) can be achieved, thereby improving the deposition uniformity of the metal electrode, facilitating the inhibition of dendrite growth on the surface of the metal electrode, and improving the self-corrosion effect occurred on the surface of the aluminum electrode. As a result, the metal-ion battery, employing the electrolyte composition, can have enhanced characteristics and prolonged lifespan.

The substituted C5-C30nitrogen-containing heterocyclic compound is a C5-C30nitrogen-containing heterocyclic compound which has at least one hydrogen atom bonded to the carbon atom of the compound that is replaced with R, wherein R can be halogen, cyano group, C1-10alkyl group, C1-10alkoxy group, C1-5aminoalkyl group, —NR1R2,

When R is C1-10alkyl group, R can be linear or branched alkyl group, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, or an isomer thereof. When R is C1-10alkoxy group, R can be linear or branched alkoxy group. For example, C1-10alkoxy group can be methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, or an isomer thereof. When R is C1-5aminoalkyl group, R can be linear or branched aminoalkyl group. For example, C1-5aminoalkyl group can be aminomethyl (with a structure of NH2CH2—), aminoethyl (with a structure of NH2C2H4—), aminopropyl (with a structure of NH2C3H6—), or an isomer thereof.

According to another embodiment of the disclosure, the additive can include 1,10-phenanthroline, 1,7-phenanthroline, 4,7-phenanthroline, 5-chloro-1,10-phenanthroline, 4-pyridinecarboxylic acid hydrazide, 8-(4-Dimethylaminophenyl)diazenyl-N,N-diethyl-10-phenylphenazin-10-ium-2-amine chloride (Janus Green B), pyridine-3-carboxylic acid, or a combination thereof.

According to embodiments of the disclosure, in the electrolyte composition of the disclosure, the molar ratio of the metal salt to the ionic liquid can be greater than or equal to 1.0, such as from 1.0 to 2.05, or from 1.1 to 2.0. For example, the molar ratio of the metal salt to the ionic liquid can be about 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0. In addition, according to embodiments of the disclosure, the amount of additive can be 0.05 wt % to 20 wt %, based on the total weight of the metal salt and the ionic liquid. When the amount of additive is too low, it is equivalent to the condition which the composition is free of the additives, and the dendritic growth on the surface of the metal electrode and the electrode self-corrosion are observed. When the amount of additive is too high, the additive is not to apt to be dissolved in the mixture of the metal salt and the ionic liquid (i.e. cloudiness and/or precipitation in the electrolyte composition are observed), thereby reducing the conductivity of the electrolyte composition and reducing the capacity of the battery employing the electrolyte composition. In another embodiment, the amount of additive can be from 0.05 wt % to 15 wt %. In yet another embodiment, the amount of additive can be from 0.05 wt % to 10 wt %.

According to embodiments of the disclosure, the electrolyte composition of the disclosure can optionally further include a solvent in order to adjust the viscosity of the composition via dilution. The solvent also facilitates the injection of the composition into the battery to be disposed between the positive electrode and negative electrode during the package of the battery, thereby enhancing the transfer of ions. The solvent can be furan-based solvent, carbonate-based solvent, ester-based solvent, ether-based solvent, benzene-based solvent, nitrile-based solvent, amidine-based solvent, or ketone-based solvent. For example, the solvent can be tetrahydrofuran (THF), dimethyl ether, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, trimethyl phosphate, dimethoxyethane, toluene, acetonitrile, dimethyl sulfoxide, dimethylformamide, acetone, or a combination thereof.

According to embodiments of the disclosure, the disclosure also provides a metal-ion battery. As shown inFIG. 1is a schematic view of the metal-ion battery100according to an embodiment of the disclosure. The metal-ion battery100can include a positive electrode10, a negative electrode12, and a separator14, wherein the separator14can be disposed between the positive electrode10and the negative electrode12to separate the negative electrode12and the positive electrode10from each other, preventing the positive electrode10from coming into direct contact with the negative electrode12. The metal-ion battery100further includes the aforementioned electrolyte composition20disposed between the positive electrode and the negative electrode in the battery. Thus, the electrolyte composition20comes into contact with the positive electrode10and the negative electrode12. The metal-ion battery can be a rechargeable secondary battery or it can be a primary battery.

According to embodiments of the disclosure, the positive electrode10can contain a positive electrode current-collecting layer11and a positive electrode active material13which is disposed on the positive electrode current-collecting layer11. According to embodiments of the disclosure, the positive electrode10can consist of the positive electrode current-collecting layer11and the positive electrode active material13. The positive electrode current-collecting layer11can include conductive carbon substrate, metal material, metal material with a porous structure, or a combination thereof. The metal material can be, for example, aluminum, nickel, copper, and molybdenum. The conductive carbon substrate can be carbon cloth, carbon felt, or carbon paper. For example, the conductive carbon substrate can have a sheet resistance from about 1 mΩ·cm2to 6 mΩ·cm2, and the carbon content of the conductive carbon substrate is greater than 65 wt %. According to embodiments of the disclosure, the metal material with a porous structure, such as three-dimensional network structure metal material (such as nickel mesh, copper mesh, or molybdenum mesh) or metal material with a foam structure (such as: nickel foam, copper foam, or molybdenum foam). According to embodiments of the disclosure, the metal material with a porous structure can have a porosity P from about 50% to 80% (such as about 60% or 70%). The porosity P can be determined by the following equation: P=V1/V2×100%, wherein V1 is the volume of the pores of the positive electrode current-collecting layer, and V2 is the volume of the positive electrode current-collecting layer. According to embodiments of the disclosure, the positive electrode current-collecting layer can be a composite layer of the conductive carbon substrate and a metal material.

According to embodiments of the disclosure, the positive electrode active material can be layered carbon material, layered double hydroxide, layered oxide, layered chalcogenide, vanadium oxide, metal sulfide, an agglomerate thereof, or a combination thereof. According to embodiments of the disclosure, the layered carbon material can be graphite, carbon nanotube, graphene, or a combination thereof. According to embodiments of the disclosure, the layered carbon material can be intercalated carbon material, such as graphite (including natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, flake graphite, or expanded graphite), graphene, carbon nanotube, or a combination thereof. According to embodiments of the disclosure, the positive electrode active material can grow directly on the positive electrode current-collecting layer, and there is no intermediate between the positive electrode active material and the positive electrode current-collecting layer. For example, the positive electrode active material can grow directly on the positive electrode current-collecting layer by chemical vapor deposition (CVD). Furthermore, the positive electrode active material can be affixed to the positive electrode current-collecting layer via an adhesive. The adhesive can be polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), carboxymethyl cellulose sodium, polyvinylidene difluoride (PVDF), styrene-butadiene copolymer, fluorinated rubber, polyurethane, polyvinylpyrrolidone, poly(ethyl acrylate), polyvinyl chloride, polyacrylonitrile, polybutadiene, polyacrylic acid, or a combination thereof. According to embodiments of the disclosure, when the positive electrode current-collecting layer is metal material with a porous structure, the positive electrode active material can further fill into the pores of the metal material.

According to embodiments of the disclosure, suitable materials of the separator14can be glass fiber, polyethylene (PE), polypropylene (PP), nonwoven fabric, wood fiber, poly(ether sulfones) (PES), ceramic fiber, or a combination thereof.

According to embodiments of the disclosure, the negative electrode12includes a negative electrode active material, wherein the negative electrode active material can include a metal or an alloy of the metal, layered carbon material, layered double hydroxide, layered oxide, layered chalcogenide, vanadium oxide, metal sulfide, an agglomerate thereof, or a combination thereof. According to embodiments of the disclosure, the metal can be sodium, potassium, beryllium, magnesium, calcium, scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, indium, thallium, tin, lead, antimony, bismuth, gallium, or aluminum. According to embodiments of the disclosure, the layered carbon material can be graphite, carbon nanotube, graphene, or a combination thereof. According to embodiments of the disclosure, the layered carbon material can be intercalated carbon material, such as graphite (including natural graphite, artificial graphite, pyrolytic graphite, foamed graphite, flake graphite, or expanded graphite), graphene, carbon nanotube, or a combination thereof. According to embodiments of the disclosure, the negative electrode12can further include a negative electrode current-collecting layer, the negative electrode active material can grow directly on the negative electrode current-collecting layer, and there is no intermediate between the negative electrode active material and the negative electrode current-collecting layer. For example, the negative electrode active material can grow directly on the negative electrode current-collecting layer by chemical vapor deposition (CVD). Furthermore, the negative electrode active material can be affixed to the negative electrode current-collecting layer via an adhesive. The adhesive can be polyvinyl alcohol (PVA), polytetrafluoroethylene (PTFE), carboxymethyl cellulose sodium, polyvinylidene difluoride (PVDF), styrene-butadiene copolymer, fluorinated rubber, polyurethane, polyvinylpyrrolidone, poly(ethyl acrylate), polyvinyl chloride, polyacrylonitrile, polybutadiene, polyacrylic acid, or a combination thereof. According to embodiments of the disclosure, when the positive electrode current-collecting layer is metal material with a porous structure, the positive electrode active material can further fill into the pores of the metal material. According to embodiments of the disclosure, the negative electrode current-collecting layer can include conductive carbon substrate, such as carbon cloth, carbon felt, or carbon paper. For example, the conductive carbon substrate can have a sheet resistance from about 1 mΩ·cm2to 6 mΩ·cm2, and the carbon content of the conductive carbon substrate is greater than 65 wt %. According to embodiments of the disclosure, the negative electrode current-collecting layer can include metal foil or metal material with a porous structure, such as three-dimensional meshwork structure metal material (such as nickel mesh, copper mesh, or molybdenum mesh) or metal material with a foam structure (such as nickel foam, copper foam, or molybdenum foam). In some embodiments, negative electrode current-collecting layer can include lithium mesh, lithium foil, lithium foam, sodium mesh, sodium foil, sodium foam, potassium mesh, potassium foil, potassium foam, beryllium mesh, beryllium foil, beryllium foam, magnesium mesh, magnesium foil, magnesium foam, calcium mesh, calcium foil, calcium foam, scandium mesh, scandium foil, scandium foam, yttrium mesh, yttrium foil, yttrium foam, titanium mesh, titanium foil, titanium foam, zirconium mesh, zirconium foil, zirconium foam, hafnium mesh, hafnium foil, hafnium foam, vanadium mesh, vanadium foil, vanadium foam, niobium mesh, niobium foil, niobium foam, tantalum mesh, tantalum foil, tantalum foam, chromium mesh, chromium foil, chromium foam, molybdenum mesh, molybdenum foil, molybdenum foam, tungsten mesh, tungsten foil, tungsten foam, manganese mesh, manganese foil, manganese, technetium mesh, technetium foil, technetium foam, rhenium mesh, rhenium foil, rhenium foam, iron mesh, iron foil, iron foam, ruthenium mesh, ruthenium foil, ruthenium foam, osmium mesh, osmium foil, osmium foam, cobalt mesh, cobalt foil, cobalt foam, rhodium mesh, rhodium foil, rhodium foam, iridium mesh, iridium foil, iridium foam, nickel mesh, nickel foil, nickel foam, palladium mesh, palladium foil, palladium foam, platinum mesh, platinum foil, platinum foam, copper mesh, copper foil, copper foam, silver mesh, silver foil, silver foam, gold mesh, gold foil, gold foam, zinc mesh, zinc foil, zinc foam, cadmium mesh, cadmium foil, cadmium foam, indium mesh, indium foil, indium foam, thallium mesh, thallium foil, thallium foam, tin mesh, tin foil, tin foam, lead mesh, lead foil, lead foam, antimony mesh, antimony foil, antimony foam, bismuth mesh, bismuth foil, bismuth foam, gallium mesh, gallium foil, gallium foam, aluminum mesh, aluminum foil, aluminum foam, titanium nitride, conductive polymer, or a combination thereof. According to embodiments of the disclosure, the metal material with a porous structure can have a porosity P from about 50% to 80% (such as about 60% or 70%). The porosity P can be determined by the following equation: P=V1/V2×100%, wherein V1 is the volume of the pores of the negative electrode current-collecting layer, and V2 is the volume of the negative electrode current-collecting layer. According to embodiments of the disclosure, the negative electrode current-collecting layer can be a composite layer of the conductive carbon substrate and a metal material. According to embodiments of the disclosure, when the negative electrode current-collecting layer is metal material with porous structure, the negative electrode active material can further fill into the pores of the metal material. According to embodiments of the disclosure, the negative electrode can consist of the negative electrode current-collecting layer and the negative electrode active material. According to embodiments of the disclosure, the material of the positive electrode10and the negative electrode12is the same, and the structure of the positive electrode10and the negative electrode12is the same.

EXAMPLES

Preparation of Electrolyte Composition

Comparative Preparation Example 1

Aluminum chloride (AlCl3) and 1-butyl-3-methylimidazolium chloride ([BMI+][Cl−]) (serving as ionic liquid) were mixed (the molar ratio of AlCl3to [BMI+][Cl−] was 1.5:1). The reactants were all transferred from a solid state to a liquid state since the reactants form a eutectic system (i.e. a melt) at room temperature. After stirring the mixture for 12 hours, Electrolyte composition (1) was obtained. Since Electrolyte composition (1) remained in a clear state with good flowability, it means that Electrolyte composition (1) was a eutectic composition.

Comparative Preparation Example 2

First, aluminum chloride (AlCl3) and 1-butyl-3-methylimidazolium chloride ([BMI+][Cl−]) were mixed (the molar ratio of AlCl3to [BMI+][Cl−] was 1.5:1). Next, 0.38 wt % of naphthalene (commercially available from Aldrich with a trade number of 184500) (hereafter noted as NAP) (based on the total weight of AlCl3and [BMI+][Cl−]) was added into the mixture. After stirring for 12 hours, Electrolyte composition (2) was obtained. Since Electrolyte composition (2) remained in a clear state with good flowability, it means that Electrolyte composition (2) was a eutectic composition.

Preparation Example 1

First, aluminum chloride (AlCl3) and 1-butyl-3-methylimidazolium chloride ([BMI+][Cl−]) were mixed (the molar ratio of AlCl3to [BMI+][Cl−] was 1.5:1). Next, 0.38 wt % of 1,10-phenanthroline (commercially available from Alfa Aesar with a trade number of A13163) (hereafter noted as 110PH) (based on the total weight of AlCl3and [BMI+][Cl−]) was added into the mixture. After stirring for 12 hours, Electrolyte composition (3) was obtained. Since Electrolyte composition (3) remained in a clear state with good flowability, it means that Electrolyte composition (3) was a eutectic composition.

Preparation Example 2

Preparation Example 2 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (serving as the additive) was replaced with 1,7-phenanthroline (commercially available from Alfa Aesar with a trade number of 30909) (hereafter noted as 17PH), Electrolyte composition (4) was obtained. Since Electrolyte composition (4) remained in a clear state with good flowability, it means that Electrolyte composition (4) was a eutectic composition.

Preparation Example 3

Preparation Example 3 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (serving as the additive) was replaced with 5-chloro-1,10-phenanthroline (commercially available from Alfa Aesar with a trade number of 31180) (hereafter noted as 110PH5Cl), Electrolyte composition (5) was obtained. Since Electrolyte composition (5) remained in a clear state with good flowability, it means that Electrolyte composition (5) was a eutectic composition.

Preparation Example 4

Preparation Example 4 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (serving as the additive) was replaced with 8-(4-Dimethylaminophenyl)diazenyl-N,N-diethyl-10-phenylphenazin-10-ium-2-amine chloride (Janus Green B) (commercially available from Acros with a trade number of Ser. No. 19/680,250) (hereafter noted as JB), Electrolyte composition (6) was obtained. Since Electrolyte composition (6) remained in a clear state with good flowability, it means that Electrolyte composition (6) was a eutectic composition.

Preparation Example 5

Preparation Example 5 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (serving as the additive) was replaced with pyridine-3-carboxylic acid (commercially available from Sigma-Aldrich with a trade number of N4126) (hereafter noted as NA), Electrolyte composition (7) was obtained. Since Electrolyte composition (7) remained in a clear state with good flowability, it means that Electrolyte composition (7) was a eutectic composition.

Preparation Example 6

Preparation Example 6 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (serving as the additive) was replaced with 4-pyridinecarboxylic acid hydrazide (commercially available from Alfa Aesar with a trade number of A10583) (hereafter noted as INH), Electrolyte composition (8) was obtained. Since Electrolyte composition (8) remained in a clear state with good flowability, it means that Electrolyte composition (8) was a eutectic composition.

Preparation Example 7

Preparation Example 7 was performed in the same manner as in Preparation Example 6 (the method for preparing Electrolyte composition (8)), except that the amount of 4-pyridinecarboxylic acid hydrazide was reduced from 0.38 wt % to 0.05 wt %, Electrolyte composition (9) was obtained. Since Electrolyte composition (9) remained in a clear state with good flowability, it means that Electrolyte composition (9) was a eutectic composition.

Preparation Example 8

Preparation Example 8 was performed in the same manner as in Preparation Example 1 (the method for preparing Electrolyte composition (3)), except that 1,10-phenanthroline (0.38 wt %) was replaced with 4-pyridinecarboxylic acid hydrazide (0.05 wt %) and pyridine-3-carboxylic acid (0.05 wt %), and Electrolyte composition (10) was obtained. Since Electrolyte composition (10) remained in a clear state with good flowability, it means that Electrolyte composition (10) was a eutectic composition.

Preparation Example 9

Preparation Example 9 was performed in the same manner as in Preparation Example 10 (the method for preparing Electrolyte composition (12)), except that 4-pyridinecarboxylic acid hydrazide (0.05 wt %) and pyridine-3-carboxylic acid (0.05 wt %) were replaced with 4-pyridinecarboxylic acid hydrazide (0.38 wt %) and pyridine-3-carboxylic acid (0.38 wt %), and Electrolyte composition (11) was obtained. Since Electrolyte composition (11) remained in a clear state with good flowability, it means that Electrolyte composition (11) was a eutectic composition.

Preparation Example 10

First, aluminum chloride (AlCl3) and 1-butyl-3-methylimidazolium chloride ([BMI+][Cl−]) were mixed (the molar ratio of AlCl3to [BMI+][Cl−] was 1.5:1). Next, based on the total weight of AlCl3and [BMI+][Cl−], 0.38 wt % of 4-pyridinecarboxylic acid hydrazide (serving as additive) and 1 wt % of tetrahydrofuran (THF) (serving as solvent) were added into the mixture. After stirring for 12 hours, Electrolyte composition (12) was obtained.

Preparation Example 11

Preparation Example 11 was performed in the same manner as in Preparation Example 10 (the method for preparing Electrolyte composition (12)), except that the amount of tetrahydrofuran was increased from 1 wt % to 5 wt %, obtaining Electrolyte composition (13).

Comparative Preparation Example 3

Aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride ([EMI+][Cl−]) (serving as ionic liquid) were mixed (the molar ratio of AlCl3to [EMI+][Cl−] was 2:1). The reactants were all transferred from a solid state to a liquid state since the reactants form a eutectic system (i.e. a melt) at room temperature. After stirring the mixture for 12 hours, Electrolyte composition (14) was obtained. Since Electrolyte composition (14) remained in a clear state with good flowability, it means that Electrolyte composition (14) was a eutectic composition.

Preparation Example 12

First, aluminum chloride (AlCl3) and 1-ethyl-3-methylimidazolium chloride ([EMI+][Cl−]) (serving as ionic liquid) were mixed (the molar ratio of AlCl3to [EMI+][Cl−] was 2:1). Next, 0.38 wt % of pyridine-3-carboxylic acid (commercially available from Sigma-Aldrich with a trade number of N4126) (hereafter noted as NA) (based on the total weight of AlCl3and [EMI+][Cl−]) was added into the mixture. After stirring for 12 hours, Electrolyte composition (15) was obtained. Since Electrolyte composition (15) remained in a clear state with good flowability, it means that Electrolyte composition (15) was a eutectic composition.

Preparation Example 13

Preparation Example 13 was performed in the same manner as in Preparation Example 12 (the method for preparing Electrolyte composition (15)), except that the amount of pyridine-3-carboxylic acid was increased from 0.38 wt % to 10 wt %, Electrolyte composition (16) was obtained. Since Electrolyte composition (16) remained in a clear state with good flowability, it means that Electrolyte composition (16) was a eutectic composition.

Preparation Example 14

Preparation Example 14 was performed in the same manner as in Preparation Example 12 (the method for preparing Electrolyte composition (15)), except that the pyridine-3-carboxylic acid (0.38 wt %) was replaced with 8-(4-Dimethylaminophenyl)diazenyl-N,N-diethyl-10-phenylphenazin-10-ium-2-amine chloride (Janus Green B) 10 wt %, Electrolyte composition (17) was obtained. Since Electrolyte composition (17) remained in a clear state with good flowability, it means that Electrolyte composition (17) was a eutectic composition.

Preparation Example 15

Preparation Example 15 was performed in the same manner as in Preparation Example 14 (the method for preparing Electrolyte composition (17)), except that the amount of Janus Green B was increased from 10 wt % to 15 wt %, Electrolyte composition (18) was obtained. Since Electrolyte composition (18) remained in a clear state with good flowability, it means that Electrolyte composition (18) was a eutectic composition.

Preparation Example 16

Preparation Example 16 was performed in the same manner as in Preparation Example 14 (the method for preparing Electrolyte composition (17)), except that the amount of Janus Green B was increased from 10 wt % to 20 wt %, Electrolyte composition (19) was obtained. Since Electrolyte composition (19) remained in a clear state with good flowability, it means that Electrolyte composition (19) was a eutectic composition.

Preparation Example 17

Preparation Example 17 was performed in the same manner as in Preparation Example 14 (the method for preparing Electrolyte composition (17)), except that the amount of Janus Green B was increased from 10 wt % to 25 wt %, Electrolyte composition (20) was obtained. Electrolyte composition (20) has good flowability, but the electrolyte composition became turbid and a precipitate formed. It means that Electrolyte composition (20) was not a eutectic composition and could not be used in the battery.

Comparative Example 1

First, an aluminum foil (with a thickness of 0.05 mm, manufactured by Alfa Aesar) was cut to obtain the negative electrode (having a size of 20 mm×20 mm). A nickel foam sheet (having a size of 100 mm×100 mm, a thickness of 0.2 mm, a porosity of 90%, and a pore diameter of 200 m) was provided. Next, the nickel foam sheet was disposed in a vacuum muffle furnace, and then hydrogen gas, argon gas (serving as carrier gas), and methane gas were introduced into the vacuum muffle furnace to perform a graphite vapor deposition (at a temperature of 900° C. to 1100° C.), obtaining a graphite material (nickel foam sheet with a graphite layer covering the surface thereof) with a graphite loading amount of about 800-1500 mg. Next, the graphite material was cut to obtain the positive electrode (i.e. graphite electrode) (having a size of 20 mm×20 mm). Next, a separator (a glass filter paper with trade No. Whatman GF/C) was provided. Next, the negative electrode, the separator, and the positive electrode were placed in sequence and sealed within an aluminum plastic pouch. Next, Electrolyte composition (1) was injected into the aluminum plastic pouch, obtaining Metal-ion battery (1).

Next, Metal-ion battery (1) was subjected to a charge-discharge testing (charged to about 2.3 V) by NEWARE battery analyzer (BST408-5V-10 A) with a current of 500 mA/g to analyze the Coulombic efficiency of Metal-ion battery (1), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion battery (1) was lower than 80%. The results are shown in Table 1.

Comparative Example 2

Comparative Example 2 was performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte composition (2), obtaining Metal-ion battery (2).

Next, Metal-ion battery (2) was subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion battery (2), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion battery (2) was lower than 80%. The results are shown in Table 1.

Examples 1-9 were performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte compositions (3)-(11) individually, obtaining Metal-ion batteries (3)-(11).

Next, Metal-ion batteries (3)-(11) were subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion batteries (3)-(11), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion batteries (3)-(11)) were lower than 80%. The results are shown in Table 1.

As shown in Table 1, in comparison with Comparative Example 1 and Comparative Example 2, the batteries as disclosed in Examples 1-11 exhibit enhanced Coulombic efficiency. It means that the deposition/dissolution uniformity of the metal electrode is improved when the nitrogen-containing heterocyclic compound additive is added into the electrolyte composition. Therefore, the metal-ion battery, employing the electrolyte composition, can have enhanced characteristics and prolonged lifespan.

Example 10 was performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte composition (12), obtaining Metal-ion battery (12).

Next, Metal-ion battery (12) was subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion battery (12), and the capacity retentions at the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion battery (12) was lower than 80%. The results show below: Metal-ion battery (12) has a Coulombic efficiency of 99.6%, the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle are 77.6% and 55.5% respectively, and the discharging capacity was lower than 80% on the 1887thcharging/discharging cycle.

Example 11 was performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte composition (13), obtaining Metal-ion battery (13).

Next, Metal-ion battery (13) was subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion battery (13), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion battery (13) was lower than 80%. The results show below: Metal-ion battery (13) has a Coulombic efficiency of 99.2%, the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle are 77.8% and 56.5% respectively, and Coulombic efficiency was lower than 80% on the 1966thcharging/discharging cycle.

Comparative Example 3

Comparative Example 3 was performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte composition (14), obtaining Metal-ion battery (14).

Next, Metal-ion battery (14) was subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion battery (14), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion battery (14) was lower than 80%. The results are shown in Table 2.

Examples 12-16 were performed in the same manner as Comparative Example 1 (the method for fabricating the Metal-ion battery (1)) except that Electrolyte composition (1) was replaced with Electrolyte compositions (15)-(19) individually, obtaining Metal-ion batteries (15)-(19).

Next, Metal-ion batteries (15)-(19) were subjected to the aforementioned charge-discharge testing to analyze the Coulombic efficiency of Metal-ion batteries (15)-(19), and the capacity retentions on the 2000thcharging/discharging cycle and the 3000thcharging/discharging cycle. Further, the number of the charging/discharging cycles was determined when the discharging capacity of Metal-ion batteries (15)-(19)) were lower than 80%. The results are shown in Table 2.

The initial aluminum foil of the negative electrode of the metal-ion battery, the aluminum negative electrode of Metal-ion battery (1) after 3000 charging/discharging cycles, and aluminum negative electrode of Metal-ion battery (8) after 3000 charging/discharging cycles were subjected to SEM (electronic scanner microscope) analysis (SEM; Model name: SU-8010, HITACHI society manufacture) and the photographs of the surface of the aluminum foils were shown inFIGS. 2-4individually. As shown inFIGS. 2-4, the initial aluminum foil has a smooth surface before use. After the assembly of battery and then performing 3000 charging/discharging cycles, the aluminum electrode of the battery would have an uneven surface and corrosion pits are produced on the surface of the aluminum electrode when the electrolyte composition is in the absence of additive. In addition, the aluminum electrode of the battery would have a smooth surface after performing 3000 charging/discharging cycles, when the electrolyte composition is in the presence of additive. It means that, due to the addition of the nitrogen-containing heterocyclic compound additive of the disclosure in the composition, the deposition/dissolution uniformity of the metal electrode and the self-corrosion effect of the surface of the aluminum electrode are improved during the charging/discharging cycles of the metal-ion battery (such as aluminum-ion battery).

It will be clear that various modifications and variations can be made to the disclosed methods and materials. It is intended that the specification and examples be considered as exemplary only, with the true scope of the disclosure being indicated by the following claims and their equivalents.