49 results about "Lithium–air battery" patented technology

The invention discloses a high-interface-stability composite solid electrolyte membrane as well as a preparation method and application thereof. The composite solid electrolyte membrane comprises a gradient aperture three-dimensional porous skeleton formed by sintering inorganic solid electrolyte particles, a polymer electrolyte filled in a pore channel, and a plastic interface stable layer positioned between the electrolyte membrane and an electrode. The preparation method comprises the following steps: preparing a gradient aperture porous framework through a pore-forming agent template method and a tape casting technology, dipping and filling a polymer electrolyte precursor solution in a solution, accelerating in-situ polymerization by adopting electric induction, and performing hot-pressing treatment. The composite solid-state electrolyte membrane has high ionic conductivity, excellent interface compatibility and high mechanical strength, can effectively inhibit the growth of lithium dendrites, can be applied to solid-state batteries such as lithium metal batteries, lithium sulfur batteries and lithium air batteries, and can remarkably prolong the cycle life and improve the safety performance of the batteries, and the preparation process is suitable for large-scale production.

The invention discloses application of a benzoquinone-based covalent organic framework material as a bifunctional photocatalyst in a photo-assisted lithium-air battery, and the benzoquinone-based covalent organic framework material is prepared by taking cyclohexanehexone octahydrate and 2, 3, 5, 6-tetraaminocyclohexane-2, 5-diene-1, 4-diketone as raw materials, ethylene glycol as a solvent and acetic acid as a catalyst through a hydrothermal reaction. And carrying out Schiff base reaction under the protection of nitrogen atmosphere. The benzoquinonyl covalent organic framework material has a large number of donor and acceptor units, has a wide visible light absorption range, can be used as a photo-assisted lithium-air battery bifunctional photocatalyst, greatly inhibits photon-generated carrier recombination, reduces the over-potential of a photo-assisted lithium-air battery, remarkably improves the battery assembly efficiency, and has a wide application prospect. And a new direction is provided for selection of photocatalysts in the field of lithium-air batteries.

The invention relates to the technical field of lithium air batteries, in particular to a lithium air battery, a battery system and a use method. A lithium air battery includes: a battery case having a positive electrode chamber; and the compression air supply assembly is arranged outside the battery shell, and the compression air supply assembly is communicated with the positive electrode chamber through a pipeline. The invention provides a lithium air battery, a battery system and a use method, and aims to solve the problem of complex internal structure of an existing air compressor.

Protected lithium electrode structure (1) for a lithium-air battery, comprising: a negative electrode current collector (3); a negative electrode active material layer (5) made of a lithium metal, a mainly lithium-containing alloy or a mainly lithium-containing compound, and stacked on the negative electrode current collector (3); and a separator (7) which is stacked on the negative electrode active material layer (5), wherein the negative electrode active material layer (5) is sealed by connecting the separator (7) and the negative electrode current collector (3) around the negative electrode active material layer (5), the separator (7) being bonded to the negative electrode current collector (3) at a circumferential edge section of the separator (7), and the negative electrode active material layer (5) being stacked onto a surface of the negative electrode current collector (3) to cover an area smaller than the area of ​​the negative electrode current collector (3), and a trapping layer (11) for finely powdered lithium, which is arranged between the negative electrode active material layer (5) and the separator (7) and has electrical conductivity via a bond on one side of the trapping layer (11) for finely powdered lithium, wherein the trapping layer (11) for finely powdered lithium is a conductive foam or a structure made of metal fiber and traps finely powdered lithium metal that is generated during charging and discharging.

Nanoporous carbon-based scaffolds or structures, and specifically carbon aerogels and their manufacture and use thereof. Embodiments include a cathode material within a lithium-air battery, where the cathode is formed of a binder-free, monolithic, polyimide-derived carbon aerogel. The carbon aerogel includes pores that improve the oxygen transport properties of electrolyte solution and improve the formation of lithium peroxide along the surface and / or within the pores of the carbon aerogel. The cathode and underlying carbon aerogel provide optimal properties for use within the lithium-air battery.

The invention belongs to the technical field of lithium batteries, and particularly relates to an MXene / COF electrode material for a photo-assisted Li-O2 / Li-CO2 battery as well as a preparation method and application of the MXene / COF electrode material. The MXene / COF electrode material is prepared by adopting an intercalation stripping technology and an in-situ polymerization growth technology, the positive electrode material with a photoelectrocatalytic property is obtained, the photoelectric characteristic of the existing MXene material is improved, the MXene material can be applied to a lithium air battery and a lithium carbon dioxide battery, the dual-function photo-assisted effect of improving the charge and discharge performance at the same time is realized, and the application prospect is wide. Due to the bifunctional photo-assisted effect, the charging voltage of the Li-O2 / Li-CO2 battery is reduced, and the discharging voltage of the Li-O2 / Li-CO2 battery is increased, so that the overpotential is reduced, and meanwhile, the photo-assisted strategy accelerates the reaction kinetics process and reduces the accumulation of adverse products, so that the stability of the battery is improved.

The present invention relates to a cathode for an air cell and a lithium-air cell comprising the same. The cathode for an air cell comprises: a porous conductive material; and an alkali-resistant compound on a surface of the porous conductive material, the alkali-resistant compound having a positive Gibbs free energy at 2 V to 4.5 V vs. Li / Li + at a pH of about 7 to about 14.

The present invention belongs to the technical field of metal-air batteries, and provides a light-assisted lithium-air battery photoelectric positive electrode, a preparation method thereof, and a light-assisted lithium-air battery. The present invention adopts nickel-doped α-ferric oxide nanospheres, conductive carbon black, and a binder to prepare a porous coating and applies it to a conductive current collector. Under light conditions, nickel-doped α-ferric oxide nanospheres are used to absorb light energy to achieve the separation of photogenerated electrons and holes. During the charging reaction, the photogenerated electrons can be transmitted to the lithium negative electrode through an external circuit and combined with lithium ions for deposition. At the same time, the photogenerated holes oxidize lithium peroxide to promote its decomposition into oxygen, reduce the battery charging overpotential, and alleviate the occurrence of side reactions, thereby improving the charge and discharge efficiency and cycle stability of the lithium-air battery. The results of the embodiment show that the lithium-air battery assembled with the light-assisted lithium-air battery photoelectric positive electrode provided by the present invention has a first cycle overpotential of 0.73V under light conditions.

The invention discloses a FeNiO / carbon nanotube / carbon foam composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium air battery materials. The melamine foam is placed in a mixed solution composed of nickel salt and iron salt, ultrasonic treatment is carried out for 10-100 min, standing is carried out for 1-12 h, drying is carried out, metal salt attached to the surface layer is removed, and FeNi / melamine foam is obtained; placing FeNi / melamine foam at the downstream of the crucible, placing a carbon source at the upstream of the crucible, and covering the crucible with a crucible cover; under the inert gas atmosphere, heating to 600-900 DEG C at the heating rate of 2-10 DEG C / min, keeping the temperature for 5-240 minutes, and naturally cooling to room temperature; and heating to 300-400 DEG C at a heating rate of 8-10 DEG C / min in an air atmosphere, preserving heat for 5-30 minutes, and cooling to room temperature to obtain the FeNiO / carbon nanotube / carbon foam composite material. According to the prepared FeNiO / carbon nanotube / carbon foam composite material, under the synergistic effect of multiple components, the charge-discharge specific capacity of a battery is greatly improved, and the service life of the battery is obviously prolonged.

The invention relates to the technical field of lithium-air batteries, in particular to an experimental device for testing a lithium-oxygen battery, which is characterized in that a testing space is arranged in a testing box body, and the lithium-oxygen battery to be tested is arranged in the testing space. The test box body is provided with a gas conveying pipe fitting communicated with the test space, a charging and discharging connector connected with two pole columns of the lithium oxygen battery to be tested, and a vibrator for carrying out vibration test on the lithium oxygen battery to be tested. The safety box is buried underground, the top of the safety box is open, and anti-explosion sand is arranged in the safety box. The crane mechanism is installed on the ground and located on the periphery of the safety box. Before the test is started, signal lines of the gas transmission pipe fitting, the charging and discharging connector and the vibrator are connected with corresponding pipelines. And then the test box body of the lithium-oxygen battery to be tested in the test space is hoisted and placed on the inner bottom wall of the safety box by using the crane mechanism. And the test is carried out after the safety box is buried by utilizing the explosion-proof sand, so that the test safety is ensured while the limit data can be obtained.

The invention relates to a three-dimensional composite material current collector for a lithium-containing battery, a preparation method of the three-dimensional composite material current collector, a lithium metal battery and a lithium air battery. The current collector is of a double-layer structure, one layer is of an electrode three-dimensional structure, the other layer is of a compact electrode structure, and the electrode three-dimensional structure is provided with finger-shaped holes; the current collector comprises a conductive skeleton and a lithium-containing solid electrolyte, wherein the conductive skeleton comprises an alloy phase formed by a high-conductivity metal and a high-lithium metal affinity metal. The conductive skeleton and the solid electrolyte are tightly compounded in a three-dimensional space to form an ion transmission channel and an electron transmission channel which are continuously interpenetrated, so that the electrolyte-current collector interface impedance can be effectively reduced. The lithium air battery assembled by the current collector shows obviously excellent electrochemical performance in the aspects of discharge capacity utilization rate, rate response capability and cycling stability, and shows good engineering application potential.

Disclosed are novel organoborane compositions of Formula (I), (II) or (III),wherein R1, R2, R3, R′, R″, n, n′, n″, m, m′, and m″ are defined hereinabove. Also disclosed is a method of using said compositions for electrolytic media in lithium rechargeable batteries, including lithium-ion or lithium-air rechargeable batteries. Also disclosed are compositions containing said Formula (I), (II) and (III) compounds with lithium salts, useful as electrolytic media or matrices.

This invention provides a metal covalent organic framework material and its preparation method, as well as a positive electrode sheet for a lithium-air battery, belonging to the field of lithium-air battery technology. The metal covalent organic framework material represented by Formula I is a one-dimensional metal covalent organic framework material, avoiding the problem of insufficient utilization of active sites within a two-dimensional layered structure, thus improving the discharge specific capacity and cycle stability of the lithium-air battery. In Formula I, the electronegativity of the two nitrogen atoms in the two pyridine rings induces local positive charges at the M center, forming strong Lewis acid sites. Simultaneously, ligand-metal charge transfer enhances the conductivity and electron delocalization of the active sites in the metal covalent organic framework material, improving the discharge specific capacity of the lithium-air battery. Furthermore, the M atoms are anchored to the metal covalent organic framework material framework through coordination bonds, maintaining the active site density and structural integrity of the metal covalent organic framework material, thereby improving the cycle stability of the lithium-air battery.

The application discloses a C / MoS2-FeMo2S4-MoC composite material and application thereof in a lithium air battery, and a preparation method of the composite material is as follows: molybdenum salt, thiourea and glucose are dissolved in deionized water, C / MoS2 material is prepared through a hydrothermal method, then dopamine is coated on the surface of the C / MoS2 material, iron salt is adsorbed on the surface of the dopamine, and C / MoS2@Fe-PDA precursors are obtained after drying; and the C / MoS2-FeMo2S4-MoC composite material is obtained by high-temperature calcination under the protection of argon. The preparation process is simple, and the cost is low; the obtained composite material has a low overvoltage, a high discharge specific capacity and excellent cycle performance when used as a lithium air battery positive electrode catalyst, and has a good research prospect.

A battery may include an anode, a cathode positioned opposite to the anode, a separator positioned between the anode and the cathode, an electrolyte dispersed throughout the cathode and in contact with the anode, and a dual-pore system. The anode may be configured to release a plurality of lithium ions. The cathode may include a plurality of pathways defined by a plurality of porous non-hollow carbonaceous spherical particles and may include a plurality of carbonaceous structures each based on a coalescence of a group of the porous non-hollow carbonaceous spherical particles. The dual-pore system may be disposed in the cathode and defined in shape and orientation by the plurality of carbonaceous structures. In some aspects, the dual-pore system may be configured to receive gaseous oxygen from the ambient atmosphere.

The present disclosure relates to a gel polymer electrolyte for a lithium-air battery including a specific amount of a zwitterionic salt and a lithium-air battery including the same and thus having an extended battery life by suppressing the volatilization of the electrolyte and imparting lithium-air battery interface stability by suppressing the formation of dendrites at the lithium anode and suppressing side reactions between the lithium anode and the liquid electrolyte. Furthermore, the use of the zwitterionic salt can increase the lithium ion transference number, thereby increasing the life of the battery.

The application provides a lithium air battery Co-Pd diatomic positive electrode catalyst and a preparation method and application thereof, and belongs to the technical field of electrochemistry and catalysis. The application comprises the following steps: mixing carbon nanotubes and an alcohol solution to obtain a carbon nanotube solution, mixing the carbon nanotube solution with a cobalt salt and a zinc salt to obtain a cobalt-containing mixture; mixing 2-methyl imidazole and an alcohol reagent to obtain a 2-methyl imidazole solution, mixing the 2-methyl imidazole solution with the cobalt-containing mixture, stirring, centrifuging and drying to obtain CoZn-CNT and the like. The lithium air battery constructed by using the catalyst provided by the application has a low charging platform (3.2 V) and a low overpotential (0.6 V), solves the problem of high overpotential (1.5 V) commonly existing in the lithium air battery, and has a high discharging platform (2.8 V) and a good discharging capacity (15000 mAhg ‑1 ).

This invention, applicable to the field of lithium batteries, provides a metal-organic nano-crosslinked network-based solid electrolyte and its preparation method, addressing the poor processability of existing inorganic solid electrolytes and the poor electrochemical stability and low ionic conductivity of polymer solid electrolytes. The electrolyte of this invention exhibits high lithium ion conductivity and a high lithium ion transference number, ensuring stable battery operation. Thanks to the polymer metal-organic nano-crosslinked network-based solid electrolyte-air cathode integrated material, the rate performance and cycling stability of lithium-air batteries are significantly improved.

The application discloses a bismuth telluride / antimony telluride heterojunction anode catalyst for a lithium air battery and a preparation method thereof, and belongs to the technical field of lithium air batteries. The bismuth telluride / antimony telluride heterojunction anode catalyst for the lithium air battery comprises bismuth telluride / antimony telluride nanosheets, the bismuth telluride / antimony telluride nanosheets are formed by epitaxial growth of antimony telluride on the surface of bismuth telluride to form a lateral heterojunction, and when the bismuth telluride / antimony telluride nanosheets are used as an anode catalyst of a lithium air battery, the specific capacity of the battery can be improved, the overpotential can be reduced, and the cycle stability can be improved; even in an air environment, the first discharge capacity of the lithium air battery can reach more than 8000 mAh / g at 500 mA / g, and the lithium air battery can be cycled more than 350 times at a high current density of 1000 mA / g and a cut-off capacity of 500 mAh / g, and excellent cycle performance is maintained.

The invention discloses a preparation method of a carbon-loaded NiCoMn (at) (alpha NiCoMn) Se Janus low-entropy alloy-medium-entropy metal selenide heterojunction catalyst, and belongs to the technical field of waste ternary lithium battery recycling, the carbon-loaded NiCoMn (at) (alpha NiCoMn) Se Janus low-entropy alloy-medium-entropy metal selenide heterojunction catalyst is prepared through Joule heating and a waste ternary lithium battery recycling process, and the catalyst has the advantages that the carbon-loaded NiCoMn (at) (alpha NiCoMn) Se Janus low-entropy alloy-medium-entropy metal selenide heterojunction catalyst is used for preparing the catalyst; niCoMn ions recovered from a waste ternary lithium battery positive electrode material are used as a transition metal source, a Pt group metal salt is used as a noble metal source, NiCoMn (at) (alphaNiCoMn) Se prepared from four metals of Pt, Ni, Co and Mn and a Se element together is loaded on a carbon carrier through a Joule heating process, and the carbon-loaded NiCoMn (at) (alphaNiCoMn) Se catalyst with a Janus structure, which is obtained by the method, is applied to a lithium air battery, so that the catalyst can be used for preparing the lithium air battery. Therefore, the catalyst has the dual-function catalytic characteristic in the lithium-air battery, and the electrochemical performance is remarkably improved.

The preparation method comprises the following steps: dissolving sodium citrate and a non-noble metal transition metal salt in deionized water to obtain a homogeneous aqueous solution, adding sodium borohydride, carrying out a reduction reaction, adding ammonium chloride, uniformly stirring, standing, and gelatinizing to obtain a precipitate, washing the precipitate with water, and drying to obtain the non-noble metal amorphous high-entropy alloy catalyst for the lithium air battery. And washing, centrifuging and freeze-drying the precipitate to obtain the non-noble metal amorphous high-entropy alloy catalyst. The method adopts a normal-temperature liquid-phase reduction method, is simple in process and convenient to operate, does not need complex equipment and harsh reaction conditions, and is suitable for large-scale production. The prepared non-noble metal amorphous high-entropy alloy catalyst has a nano porous structure, has a high specific surface area and a high electrochemical active area, and shows excellent catalytic activity in a lithium air battery.

Featuring a lithium-air battery (1A): a plurality of lithium anode compounds (8); and an air electrode (9A), wherein each comprises the plurality of lithium anode compounds (8): a plate-shaped or strip-shaped anode current collector (5); two plate-shaped anode layers (15) made of metallic lithium, a lithium-rich alloy or a lithium-rich compound and arranged to sandwich around part of the anode current collector (5), two plate-shaped insulating layers (12) made of lithium-ion conductivity glass-ceramic and arranged to sandwich another part of the anode current collector (5) and the two anode layers (15) together; and a connection (16) which is provided to connect and close outer circumferential areas of the two insulating layers (12), wherein the remainder of the anode current collector (5) between the two insulating layers (12) is exposed to the outside, and the air electrode (9A) comprises: an air electrode layer (13A) containing an electrically conductive material and facing at least one of the two insulating layers (12); and a plate-shaped or strip-shaped air electrode current collector (6) electrically connected to the air electrode layer (13A), characterized by the fact that the air electrode layer (13A) is folded in a zigzag pattern, and each lithium anode assembly (8) of the plurality of lithium anode assemblies (8) is sandwich-like surrounded by planar regions (13b) of the air electrode layer (13A), each of which is located between fold lines (13a) of the air electrode layer (13A).

The invention discloses a bismuth telluride / antimony telluride heterojunction positive electrode catalyst for a lithium air battery, a preparation method of the bismuth telluride / antimony telluride heterojunction positive electrode catalyst and the lithium air battery, and belongs to the technical field of lithium air batteries. The bismuth telluride / antimony telluride heterojunction positive electrode catalyst for the lithium air battery comprises a bismuth telluride / antimony telluride nanosheet, the bismuth telluride / antimony telluride nanosheet is obtained by forming a transverse heterojunction through epitaxial growth of antimony telluride on the surface of bismuth telluride, and when the bismuth telluride / antimony telluride heterojunction positive electrode catalyst serves as the positive electrode catalyst of the lithium air battery, the specific capacity of the battery can be improved; compared with the prior art, the lithium-air battery prepared by the preparation method has the advantages that the lithium-air battery prepared by the preparation method disclosed by the invention has the advantages that the overpotential is reduced, the cycling stability is improved, the first discharge capacity of the lithium-air battery at 500mA / g can still reach 8000mAh / g or above even in an air environment, meanwhile, the lithium-air battery can be circulated for 350 circles or above under the high current density of 1000mA / g and the cut-off capacity of 500mAh / g, and the excellent cycling performance is kept.

The invention relates to the technical field of battery recycling and electro-catalytic materials, and discloses a preparation method of a Fe-C-based lithium-air battery positive electrode material, which comprises the processes of pretreatment and multi-stage separation, iron-containing waste material enrichment, waste material synergistic mixing and in-situ reduction calcination. The Fe-C composite material with uniformly dispersed nano-iron particles is successfully constructed through an in-situ carbon thermal reduction technology, and is applied to a lithium-gas battery to realize gt; 5000 mAh g <-1 > and lt; the overpotential of 2 V provides a new path for the development of an efficient lithium-air battery positive electrode catalyst; meanwhile, low-value iron-containing waste residues and high-molecular diaphragms or packaging skins in the waste lithium batteries are directly converted into the Fe-C catalytic positive electrode material of the lithium-air battery with high additional value, so that the economic value is created, the environmental disposal risk of the Fe-C catalytic positive electrode material is thoroughly eliminated, and the unification of high-value utilization of wastes and environmental benefits is realized.

A lithium ion conducting protective film produced using a layer-by-layer assembly process. The lithium ion conducting protective film is assembled on a substrate by a sequential exposure of the substrate to a first poly(ethylene oxide) (PEO) layer including a cross-linking silane component on the first side of the substrate, a graphene oxide (GO) layer on the first PEO layer, a second poly(ethylene oxide) (PEO) layer including a cross-linking silane component on the GO layer and a poly(acrylic acid) (PAA) layer on the second PEO layer. The film functions as a lithium ion conducting protective film that isolates the lithium anode from the positive electrochemistry of the cathode in a lithium-air battery, thereby preventing undesirable lithium dendrite growth.

Disclosed are an electrolyte membrane for a lithium-air battery, a method of manufacturing the same, a cathode for a lithium-air battery, a method of manufacturing the same, and a lithium-air battery including the electrolyte membrane and the cathode. Particularly, the lithium-air battery includes i) an electrolyte membrane, which is manufactured using an inorganic melt admixture including two or more nitrogen-oxide compounds and thus may have a very low eutectic point, and ii) a cathode, which is manufactured by reducing a metal at a fast speed on a carbon material. As such, the lithium-air battery is capable of stably operating even at low temperatures and providing high power output.

The invention relates to the technical field of lithium air battery electrolyte, in particular to electrolyte for a lithium air battery and the lithium air battery. The electrolyte for the lithium air battery comprises a functional additive, a lithium salt and a solvent, the functional additive comprises tin tetrachloride and 1, 8-diiodo-octane, the concentration of the tin tetrachloride in the electrolyte is 0.01-0.1 mol / L, and the concentration of the 1, 8-diiodo-octane in the electrolyte is 0.05-0.2 mol / L. The electrolyte provided by the invention synchronously realizes dual functions of reducing overpotential by a redox medium and inhibiting dendritic crystal growth by constructing an artificial SEI film in situ on a negative electrode in a battery cycle process, so that long-acting protection on the lithium negative electrode is achieved, the long cycle stability of the battery is remarkably improved, and the electrolyte has very high practical value.

The application discloses a kind of MoS2-coated porous M-N-C single-atom catalyst and its application in lithium-air battery, first by chelating agent transition metal ion chelation and anchor on porous carbon carrier, then mixed with nitrogen source precursor and calcined, obtain with porous nitrogen-doped carbon as carrier, load transition metal single atom M Material, again by hydrothermal sulfidation method and high-temperature calcination layer MoS2 Nanometer sheet, obtain target catalyst material.The composite material obtained by the application has higher mass transfer efficiency, higher oxygen reduction activity and stability in acidic and alkaline medium, and has lower overvoltage, high discharge specific capacity and excellent cycle performance when used as lithium-air battery catalyst, and has good research prospect.

The invention relates to the technical field of electrochemical energy storage, and discloses a lithium air battery gas circulating pump, a control method thereof and a power generation system.The lithium air battery gas circulating pump comprises a pump body used for forming a gas storage cavity, and the pump body is configured to deform under the action of current so as to change the size of the gas storage cavity; the air inlet channel is formed on the pump body, is communicated with the air storage cavity and is used for sucking air; the air outlet channel is formed in the pump body, communicates with the air storage cavity and is used for discharging air; the air inlet element is arranged in the air inlet channel and is configured to control air inlet flow when the volume of the air storage cavity is changed; and the air outlet element is arranged in the air outlet channel and is configured to control the air outlet flow when the volume of the air storage cavity is changed. According to the scheme, a motor and a transmission mechanism are replaced, and energy consumption and operation noise are remarkably reduced; and meanwhile, due to the integrated design, extra assemblies are reduced, the occupied volume is reduced, and the problems that an electric circulating pump is high in energy consumption, large in volume and high in noise in the related technology are solved.

The utility model provides an easy-to-assemble lithium air battery mould which comprises a battery shell, a positioning chute, a limiting clamping groove, a battery top cover, a rotating groove, a locking clamping block, a rotating rod, a limiting block and a rotating seat, the positioning chute is formed in the battery shell, the limiting clamping groove is formed in the positioning chute, the battery top cover is arranged above the battery shell, and the locking clamping block is arranged on the battery top cover. A rotating groove is formed in the battery top cover, a locking clamping block is arranged in the battery top cover, a rotating rod is rotationally arranged in the battery top cover, a limiting block is arranged at the lower end of the annular side face of the rotating rod, and a rotating seat is clamped to the annular side face of the rotating rod. The combined battery is reasonable in structure, easy and convenient to operate and high in practicability, and the battery shell and the battery top cover can be combined, mounted and dismounted conveniently.