158results about "Zinc-halogen accumulators" patented technology

The invention discloses a zinc-iodine battery positive electrode material based on corn straw shell derived porous carbon and a preparation method of the zinc-iodine battery positive electrode material. According to the material, corn straw shells serve as the sole carbon source, an indigenous nitrogen-doped biomass charcoal carrier with a hierarchical pore structure is prepared through pre-carbonization and KOH activation processes, and the material is characterized in that the specific surface area is larger than or equal to 1500 m < 2 > / g, and the micropore proportion is larger than 90%. The iodine is loaded on the carrier (the iodine content is greater than or equal to 45wt%) through a vacuum sublimation method to form the indigenous nitrogen-doped biomass charcoal / iodine composite material. According to the positive electrode material, through the synergistic effect of physical confinement and pyridine nitrogen chemical adsorption, the multi-iodide shuttle effect is effectively inhibited, so that the capacity retention rate of the zinc-iodine battery is greater than or equal to 93% after 40000 cycles under the current density of 2A g <-1 >, and the capacity retention rate is greater than 45% under the rate of 10A / g. The method has double benefits of agricultural waste resource utilization and high-performance energy storage device development.

The invention belongs to the technical field of zinc battery electrolyte, and discloses application of pyridine hydrochloride as an electrolyte additive in stabilizing a zinc negative electrode and realizing four-electron transfer of a zinc-iodine secondary battery. The hydrochloride containing the pyridine structure is used as an electrolyte additive, molecules of the pyridine structure are adsorbed on the surface of the zinc negative electrode to form a shielding layer, the deposition / stripping reversibility of the zinc negative electrode is improved, stabilization of the zinc negative electrode can be achieved, and the problems of zinc dendritic crystal, corrosion and hydrogen evolution are solved. Meanwhile, molecules with pyridine structures can activate and stabilize I- / I0 / I < + > four-electron redox reaction, inhibit I < + > hydrolysis side reaction and improve the energy density and cycling stability of the zinc-iodine battery. The problem of poor electrochemical deposition / stripping reversibility of a zinc negative electrode and the problem of poor stability of positive valence I < + > species of an iodine positive electrode of a four-electron transfer reaction are solved. The electrolyte containing the additive is low in cost, simple in method, easy to produce and high in practical value.

The invention relates to an aqueous zinc-iodine battery electrolyte containing a phenolic additive, and a preparation method and application thereof, and belongs to the technical field of aqueous zinc-iodine batteries. The invention aims to solve the technical problems of serious multi-iodide shuttling and negative electrode by-products of the existing aqueous zinc-iodine battery. The preparation method of the aqueous zinc-iodine battery electrolyte containing the phenolic additive comprises the following steps: dissolving zinc salt and the phenolic additive in deionized water, and fully stirring and mixing to obtain the aqueous zinc-iodine battery electrolyte containing the phenolic additive. The phenolic additive used in the application can accelerate conversion from I3-to I-, accelerate iodine conversion reaction kinetics and reduce generation of polyiodide, so that shuttling of the polyiodide is effectively inhibited, a phenolic additive monomer is adsorbed on the surface of a zinc negative electrode, contact between Zn < 2 + > and water molecules is reduced, and generation of zinc negative electrode by-products is inhibited; the zinc-iodine battery also has the advantages of being easy to manufacture and low in cost.

The invention discloses a two-phase electrolyte, a preparation method thereof and a liquid energy storage battery system, and belongs to the technical field of electrochemical energy storage. According to the invention, a liquid-liquid double-phase electrolyte is composed of a water-phase electrolyte and an organic-phase electrolyte, wherein the organic-phase electrolyte contains a coupling system of 1-(methyl-decyl)-3-methylimidazolium bromide, tris (methyl-decyl) methyl ammonium bromide and (10-octadecyl) alkyl trimethyl ammonium bromide in a molar ratio of (5-7): (2-4): 1. During charging, positive electrode bromide ions are subjected to an oxidation reaction to generate a bromine simple substance, and meanwhile, the bromine simple substance and a coupling system of the quaternary ammonium bromide compound and the bromine complexing agent provided by the invention form a stable polybromine complex product, so that the polybromine complex product is prevented from being migrated into a water-phase electrolyte, and the purpose of improving the stability of the water-phase electrolyte in the absence of a diaphragm is achieved. The self-discharge reaction of bromine is significantly inhibited at a high temperature exceeding the boiling point temperature of bromine, the coulombic efficiency and energy efficiency of the liquid energy storage battery are improved, the system cost is reduced, and the long-term cycle stability of the liquid energy storage battery is improved.

The invention discloses a graphene / polyaniline composite film with a gradient structure and a preparation method and application thereof, the preparation method comprises the following steps: S1, preparing a coating template, and uniformly coating the coating template with a graphene oxide dispersion liquid to obtain a graphene oxide porous template; s2, performing electrochemical reduction on the graphene oxide porous template to obtain a reduced graphene oxide porous template; and S3, carrying out polyaniline electrodeposition on the reduced graphene oxide porous template to obtain the graphene / polyaniline composite film with a gradient structure. The graphene / polyaniline composite film prepared by the invention has a gradient structure, and can improve various ion energy storage characteristics and conductivity of the material.

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a low-temperature aqueous electrolyte for anchoring I < + > ions based on a double-coordination structure and a low-temperature four-electron aqueous zinc-iodine battery. The low-temperature aqueous electrolyte is a mixed solution of a zinc salt, an electrolyte additive and water, and the low-temperature aqueous electrolyte comprises 2-5 mol / L of the zinc salt and 0.3-0.6 mol / L of the electrolyte additive; the zinc salt is zinc perchlorate or zinc tetrafluoroborate. The low-temperature four-electron aqueous zinc-iodine battery comprises the low-temperature aqueous electrolyte. Compared with the prior art, the invention at least has the following beneficial effects: (1) the corrosion risk caused by chloride ion concentration is reduced; (2) efficient four-electron iodine positive electrode reaction is realized; and (3) obtaining the low-temperature four-electron aqueous zinc-iodine battery.

According to one aspect, an additive for an iron negative electrode of an alkaline electrochemical cell may comprise a powder of discrete particles comprising agglomerated particles comprising at least one metal sulfide.

The invention relates to the field of nano materials and electrochemical technology materials, in particular to a melamino-formaldehyde / MXene composite material, a derived carbon material thereof, a preparation method and application. According to the preparation method disclosed by the invention, MXene is taken as a substrate, and protonated melamine formaldehyde molecules are inserted into MXene layers through an electrostatic self-assembly effect, so that the melamine formaldehyde / MXene composite material is synthesized; and carrying out high-temperature calcination on the basis to prepare the melamine formaldehyde / MXene composite material derived carbon material. According to the invention, active sites for adsorption and catalytic conversion of iodine species are provided while self-stacking of MXene is solved, and the melamine formaldehyde / MXene composite material is used as the positive electrode material of the aqueous zinc-iodine battery, so that the iodine species can be effectively anchored, and the active sites for catalytic conversion of iodine are fully provided; the reversibility and the structural stability of the electrode reaction are enhanced, so that the electrochemical performance of the battery is greatly improved.

A rechargeable lithium battery includes an electrolyte. The electrolyte comprises a non-aqueous organic solvent, a lithium salt, and an additive including an azide group and a sulfonyl group substituted with a halogen element.

The invention relates to an iodine-loaded positive electrode for a zinc-iodine battery and a preparation method and application of the iodine-loaded positive electrode, and belongs to the technical field of positive electrode materials for zinc-iodine batteries. The preparation method of the iodine-loaded positive electrode for the zinc-iodine battery comprises the following steps: mixing an iodine-loaded carbon material, conductive carbon black, a polysaccharide binder and deionized water in proportion, grinding into slurry, uniformly coating a current collector with the slurry, and drying to obtain the iodine-loaded positive electrode for the zinc-iodine battery. As the polysaccharide binder is rich in a large number of active functional groups (hydroxyl, carboxyl and the like), dissolution of active iodine and a shuttle effect of polyiodide can be inhibited through a chemical adsorption effect, corrosion to a zinc negative electrode caused by attenuation of battery capacity and shuttle of the polyiodide is avoided, and the polysaccharide binder has a good application prospect in the zinc-iodine battery.

The invention relates to the technical field of electrochemical energy storage, in particular to a polyaniline and carbon powder composite material and a preparation method and application thereof. The composite material comprises a current collector, polyaniline and carbon powder, wherein the polyaniline and the carbon powder are loaded on the current collector; the polyaniline and the carbon powder are uniformly distributed. Preferably, the carbon powder is functionalized carbon powder, and the carbon powder is selected from one or more of a carbon nanotube, activated carbon or graphene; the functionalized carbon powder is carboxylated carbon powder or hydroxylated carbon powder; the polyaniline and the functionalized carbon powder form a three-dimensional network structure, and a hydrogen bond is formed between the polyaniline and the functionalized carbon powder. A hydrogen bond formed between polyaniline and functionalized carbon powder can effectively inhibit dissolution of the positive electrode material in a zinc salt electrolyte containing iodide ions, and the stability of the positive electrode material structure is enhanced. Meanwhile, the reduction unit of bipolar polyaniline can effectively catalyze the oxidation-reduction reaction of I- / I0 and anchor the polyiodide ions, so that the shuttle side reaction of the polyiodide ions is inhibited, the growth of zinc dendrites is reduced, and the specific capacity and the cycling stability of the organic matter composite positive electrode are further remarkably improved. Besides, carboxyl and / or hydroxyl functional groups contained in the functionalized carbon powder provide certain protons for polyaniline, and energy storage is carried out through intercalation and deintercalation of the protons, so that PANI redox reaction kinetics is accelerated, and the electrolytic type aqueous zinc-iodine battery with high energy density and long service life is constructed.

The invention relates to an electrolyte for synergistically stabilizing positive electrode iodine multi-electron reaction through four-combination zinc salt and a high-surface-capacity zinc-iodine soft package battery. The electrolyte comprises the four-combination zinc salt and water, in the electrolyte, the total concentration of zinc ions in the four combinations of zinc salts is 2 + / -0.2 mol / L; the four-combination zinc salt is a four-combination zinc salt; the SO4 < 2-> in the electrolyte buffers the pH value of a system, so that side reaction of a negative electrode is reduced; cH3COO <-> can be cross-linked with I3 <->, so that shuttling of polyiodide is inhibited, and reversibility of a two-electron reaction is enhanced; bromide ions Br <-> in the electrolyte are chemically combined with I < + > through isohalogen to excite four-electron reaction; the trifluoromethanesulfonate OTf <-> with strong electronegativity surrounds the positive electricity I < + > by virtue of an ion atmosphere effect, so that active water molecule attack hydrolysis failure is avoided, a synergistic stable positive electrode iodine multi-electron reaction is realized, and the high-surface-capacity zinc-iodine soft package battery is beneficial to promoting the development of the zinc-iodine battery to practical application.

The invention discloses a zinc-iodine battery positive electrode material and a preparation method and application thereof, the zinc-iodine battery positive electrode material comprises carbon cloth, a covalent organic framework and an active substance, the covalent organic framework is 8F-COF, the covalent organic framework 8F-COF grows on the carbon cloth in situ, and the active substance is adsorbed on the carbon cloth. The material is flexible and self-supporting, energy storage is further improved, the service life of the zinc-iodine battery is further prolonged, an 8F-COF material is grown on carbon cloth in situ, 8F-COF has a microporous structure containing F atoms, when polyiodide ions pass through the porous structure, the 8F-COF connects polyiodide to a polymer skeleton through an aromatic nucleophilic substitution reaction, and thus the energy storage capacity of the zinc-iodine battery is improved. The iodide is effectively inhibited through space and electrostatic hindering, and the shuttle effect is reduced. And after being loaded with iodine, the material can be directly used as an electrode material without adding any conductive agent and binder.

The invention relates to an aqueous zinc-iodine battery electrolyte containing an amino acid additive and a preparation method and application thereof, and belongs to the technical field of aqueous zinc-iodine batteries. The preparation method of the aqueous zinc-iodine battery electrolyte containing the amino acid additives comprises the following steps: fully stirring and mixing zinc salt, D-penicillamine and deionized water according to a certain proportion to obtain the aqueous zinc-iodine battery electrolyte containing the amino acid additives. The amino acid-containing additive D-penicillamine used in the invention is preferentially coordinated with I-, and due to the lack of free I-in the reaction, the generation of polyiodide and the dissolution of I2 are inhibited, so that the shuttle effect is inhibited; the amino acid-containing additive D-penicillamine also participates in a Zn < 2 + > solvation sheath layer, so that the tendency of desolvation and Zn < 2 + > migration is improved, and the generation of zinc negative electrode byproducts is inhibited; in addition, the aqueous zinc-iodine battery electrolyte containing the amino acid additive D-penicillamine is simple in preparation method and low in cost.

The invention discloses a preparation method of a Zr-MOF nano material, which comprises the following steps: adding deionized water into a reaction mixture consisting of zircon salt, 4 ', 4', 4 ', 4'-(ethylene-1, 1, 2, 2-tetraalkyl) tetra ([1, 1 '-biphenyl]-4-carboxylic acid), an acid regulator and an organic solvent to form a mixed solution, heating and reacting in a high-pressure reaction kettle, and cooling to room temperature to obtain the Zr-MOF nano material. And centrifugally collecting and cleaning a product, and drying in a dark place to obtain the Zr-MOF nano material. According to the application of the Zr-MOF nano material in the water-based zinc-iodine battery, the Zr-MOF nano material and iodine are prepared into a composite material, then the composite material is prepared into electrode slurry, the surface of a stainless steel mesh is coated with the electrode slurry, and the electrode slurry is dried to serve as an electrode plate of the water-based zinc-iodine battery. The preparation process is simple, Zr-MOF nano-materials with different structures can be obtained by adjusting the deionized water content of the system, and the Zr-MOF nano-materials can be applied to an electrode plate of an aqueous zinc-iodine battery to improve the cycle performance of the battery.

The invention relates to the technical field of zinc-iodine battery electrolyte, in particular to aqueous zinc-iodine electrolyte as well as a preparation method and application thereof. The aqueous zinc-iodine battery electrolyte contains an additive and a zinc salt, the molar concentration of the additive is 0.15 M to 0.8 M, and the additive is selected from one or more of triethylamine hydrochloride, 1-butyl-1-methylpyrrolidine chloride, 1, 3-dimethylimidazole chloride, pyridine hydrochloride, aniline hydrochloride, guanidine hydrochloride and 1-ethyl-3-methylimidazole chloride. The method can directionally regulate and control zinc negative electrode deposition and iodine positive electrode reaction kinetics, realizes four-electron reversible conversion, promotes uniform deposition of zinc ions and inhibits side reactions during charging, inhibits multi-iodide shuttle and I < + > hydrolysis during discharging, and has wide application prospects in the zinc-iodine battery electrolyte industry.

The invention belongs to the technical field of zinc-iodine batteries, and particularly relates to doped polyaniline, a preparation method thereof and a zinc-iodine battery. The preparation method comprises the following steps: in an acidic environment, mixing substituted aniline, aniline and an oxidizing agent to obtain a mixed solution, and carrying out oxidative polymerization reaction to obtain doped polyaniline; wherein a substituent group of the substituted aniline is an electron withdrawing group; the number of the substituent group is 1; the molar ratio of the substituted aniline to the aniline is (5-25): 100; the positive electrode material in the zinc-iodine battery prepared from the doped polyaniline has high specific capacity and cycling stability.

The invention relates to a multi-metal hydroxide and iodine composite material as well as a preparation method and application thereof. According to the invention, efficient chemical adsorption of negatively charged iodine species (such as I <-> and I3) in the electrolyte is realized by utilizing the unique layered structure and the characteristic that the surface of the multi-metal hydroxide material is positively charged, so that the iodine-loaded positive electrode material is successfully prepared. The physical confinement and strong electrostatic interaction of the material can effectively anchor an iodine active substance, inhibit the dissolution and shuttle effect of polyiodide ions, and significantly reduce the loss of the active substance in the cycle process. Meanwhile, bromide ions or chloride ions are introduced into the electrolyte to anchor I < + >, so that a four-electron transfer reaction mechanism of iodine is realized, and the specific capacity of the battery is greatly improved. Experimental results show that the capacity retention rate of the zinc-iodine battery adopting the positive electrode material reaches 88% or above after circulation for 30000 times under the current density of 10 Ag <-1 >, and the zinc-iodine battery shows excellent high-capacity performance and long circulation stability. The invention provides a new technical scheme for developing a high-performance aqueous zinc-iodine battery, and has a wide application prospect in the field of energy storage.

The invention belongs to the technical field of electrochemical energy storage, and discloses an electrolyte for a zinc-bromine flow battery, a preparation method of the electrolyte and the zinc-bromine flow battery, raw materials of the electrolyte comprise the following components: zinc salt, potassium salt, an additive and a solvent; the potassium salt is a compound mixture of potassium bromide and potassium bromate; the additive comprises an organic complexing agent and an inorganic corrosion inhibitor; wherein the organic complexing agent comprises an organic zinc complexing agent and an organic bromine complexing agent; the organic zinc complexing agent is crown ether; the organic bromine complexing agent is imidazole bromine salt or pyridine bromine salt; the inorganic corrosion inhibitor is a compound of sodium molybdate, zinc sulfate, sodium dihydrogen phosphate and deionized water; growth of zinc dendrites can be remarkably inhibited, the energy density of the battery is improved, and escape of hydrogen bromide is effectively prevented, so that the performance and the stability of the zinc-bromine flow battery are comprehensively improved, the service life of the battery is prolonged, and the use cost and the safety risk of the battery are reduced.

The invention provides a dry-process low-temperature pulse iodine positive electrode preparation method and a battery, and relates to the technical field of iodine positive electrode preparation, the iodine positive electrode preparation method comprises the following steps: mixing elemental iodine with activated carbon to obtain a carbon-iodine composite material, then putting the solid powdery carbon-iodine composite material, a conductive agent and polytetrafluoroethylene into a high-speed stirrer, and stirring at a high speed; and sequentially carrying out constant-speed intermittent pulse stirring, speed-reducing pulse stirring and speed-increasing pulse stirring, and finally rolling to obtain the iodine positive electrode. According to the stirring operation, the temperature rise effect in the high-speed stirring process is inhibited, the mixture obtained after polytetrafluoroethylene fiberization is obtained through low-temperature pulse stirring, the surface of the prepared iodine positive plate is smooth and flat, the cracking phenomenon does not exist, the shearing force is regulated and controlled through low-temperature pulse stirring, mechanical disturbance is weakened, and the iodine positive plate has the good application prospect. And the temperature is reduced to inhibit thermal desorption of iodine molecules, so that the damage to the iodine adsorption effect of porous carbon is reduced, and the mechanical strength and electrochemical performance of the electrode are remarkably improved.

The invention belongs to the technical field of aqueous zinc-iodine batteries, and particularly relates to an aqueous zinc-iodine battery with high area specific energy, quick charge and long service life and a preparation method. According to the high-area-specific-energy fast-charging long-life aqueous zinc-iodine battery provided by the invention, the aqueous zinc-iodine battery which is cooperatively modified by simultaneously introducing the organic sulfonium salt into the positive electrode and the electrolyte can stably provide the capacity of 3.3 mA h / cm < 2 > (the running duration exceeds 110 days, and the capacity retention rate is-100%) under the high load of 25 mg / cm < 2 >, and the ultrahigh rate performance of 100 mA / cm < 2 > is shown; a new scheme is provided for constructing the zinc-iodine battery with high magnification and long service life, and the zinc-iodine battery serves as an energy storage device with excellent performance and is applied to multiple fields such as peak regulation and frequency modulation of a power grid; the technical problem that a high-performance aqueous zinc-iodine battery is lacked in the prior art is solved.

This invention provides a modified positive electrode structure, a zinc-vanadium battery, and a method for preparing the same. [Solution] The zinc-vanadium battery comprises a modified positive electrode structure (including a positive electrode and a modified layer), a separator, a negative electrode, and an aqueous electrolyte. The positive electrode contains titanium. The modified layer is located on the positive electrode and contains 70-95 parts by weight of vanadium-based material, 3-45 parts by weight of conductive agent, and 3-45 parts by weight of binder. The separator is located on the modified layer. The negative electrode contains zinc and is located on the separator. The positive electrode, modified layer, separator, and negative electrode are all in the aqueous electrolyte. In the X-ray diffraction pattern of the vanadium-based material measured by XRD using CuKα1 rays, the peak intensity at 2θ=8°±1.0° is I8, and the peak intensity at 2θ=20°±1.0° is I 20 In that case, I8 and I 20 The ratio (I8 / I 20 ) is 0 <I8 / I 20 The condition ≤ 1.4 is satisfied. Furthermore, a modified cathode structure, a method for preparing the modified cathode structure, and a method for preparing a zinc-vanadium battery are also provided.

The disclosure relates to an ionic liquid additive that is useful in an electrolyte solution for an electrochemical device. The ionic liquid additive is capable of interacting with polyiodide and / or polybromide species to mitigate shuttle effect for the electrochemical device and stabilise the positive electrode and the negative electrode of the electrochemical device.

The invention discloses a water-based binder, a zinc-iodine battery positive pole piece and a preparation method and application of the zinc-iodine battery positive pole piece. The preparation method of the water-based binder comprises the following steps: mixing polyethyleneimine, methyl iodide and a solvent, and carrying out graft polymerization reaction to obtain the water-based binder. The aqueous binder provided by the invention can keep excellent electrochemical stability in an aqueous electrolyte, so that the assembled zinc-iodine battery has long cycle performance; the preparation method of the aqueous binder provided by the invention is simple and environment-friendly, is more suitable for industrial large-scale production, and has a wide industrial application prospect.

The problem to be solved by the present invention is to provide a fluoride ion secondary battery having a larger battery capacity than before. To solve the above problems, there is provided a negative electrode for a fluoride ion secondary battery containing zirconium fluoride as a negative electrode active material and a fluoride ion secondary battery equipped with the negative electrode. The average particle size of zirconium fluoride can be 100 nm or less, and the content of zirconium fluoride in the negative electrode for a fluoride ion secondary battery can be less than 50% by mass. The negative electrode active material may further contain metallic zirconium, the average particle size of metallic zirconium can be 75 μm or less, and the content of metallic zirconium in the negative electrode for a fluoride ion secondary battery can be 8% by mass or less.

A battery module (400) that is a static, open pool single cell battery which may have electrode elements (442, 443) of the same polarity spaced apart but electrically connected in parallel to one another and suspended from a common bus into a common electrolyte pool (405), in addition to a battery box (400) that receives a plurality of electrode elements into the common electrolyte pool for the open pool battery. The electrode elements (442, 443) are alternating cathode elements (442) and anode elements (443). A method for manufacture of the battery module is also described.

An amphoteric ion exchange separator for a redox battery according to various embodiments of the present invention may comprise a polymer matrix into which a zwitterionic functional group having a quaternary ammonium group and a sulfonic acid group is introduced.

Provided is a fluoride ion secondary battery having a capacity larger than that of a conventional one. The fluoride ion secondary battery has a negative electrode including zirconium fluoride as a negative electrode active material. The zirconium fluoride may be in the form of particles with an average particle size of 100 nm or less, and the negative electrode may have a zirconium fluoride content of less than 50 % by mass. The negative electrode active material may further include metallic zirconium, which may be in the form of particles with an average particle size of 75 μm or less. The negative electrode may have a metallic zirconium content of 8% by mass or less.

Provided herein are phosphorus battery electrolyte additive chemicals for use in aqueous batteries that prevent self-discharge in the form of corrosion and hydrogen evolution, which increases the efficiency and extends the shelf-life of the batteries.

The invention belongs to the technical field of electrochemical energy storage, and particularly relates to an in-situ electropolymerizable melamine / activated carbon composite material as well as a preparation method and application thereof. The composite material comprises active carbon and melamine loaded on the active carbon, wherein the melamine is stacked on the active carbon in a nano-particle form; in the composite material, the doping amount of the molecular catalyst is 1 / 3-2 / 3. When the prepared melamine / activated carbon composite material is used in a prepared zinc-iodine battery, small molecules are subjected to in-situ electropolymerization to generate a polymer, the polymer has excellent electrochemical performance as a positive electrode material of the zinc-iodine battery, the iodine storage capacity and the zinc storage capacity reach 1.1 mAh / cm < 2 > under the small current density of 2mA / cm < 2 >, and when the current density is 30mA / cm < 2 >, the specific capacity still reaches 0.78 mAh / cm < 2 >. In addition, under the current density of 30mA / cm < 2 >, the capacity is still 0.55 mAh / cm < 2 > after 20000 cycles of reversible circulation. And the capacity reaches 1.55 mAh / cm < 2 > under the condition that the loading capacity of the catalytic material reaches up to 8mg / cm < 2 > and the current density is 10mA / cm < 2 >. Therefore, the prepared assembled zinc battery has relatively high specific capacity and long cycle life.