Electrodeposition manganese oxide battery

Abstract

The invention discloses an electrodeposited manganese oxide battery, belonging to the technical field of battery electrolyte. The electrodeposited manganese oxide battery of the invention comprises an electrolyte, wherein the electrolyte comprises a manganese source and an additive; the additive comprises a metal compound and / or a hygroscopic agent. The invention adds a metal compound and / or a hygroscopic agent to the electrolyte, and by replenishing the water lost by the electrolyte during the electrodeposition of manganese oxide, a dynamic balance is achieved inside the battery, thereby alleviating the problem of battery failure due to bloating, and achieving the purpose of improving battery performance.

Description

Technical Field

[0001] The invention relates to the technical field of battery electrolyte, in particular to an electrodeposition manganese oxide battery. Background Art

[0002] Compared with lithium-ion batteries, aqueous zinc-ion batteries are safer and easier to produce. Zinc-ion batteries are widely used in wearable electronics, medical electronics, and low-power IoT products due to their high safety and low cost. The assembly of flexible zinc-ion batteries is generally divided into six steps, and the more steps, the longer the production time and cost.

[0003] In the prior art, the production steps can be reduced and the production efficiency can be improved by electrodeposition of manganese oxide. However, the existing technology of electrodeposition of manganese oxide often has problems such as the Mn deposited on the electrode falling off, the amount of electrodeposited manganese oxide is too small, resulting in poor battery performance, and low-concentration salt electrolytes are often used in the production process, which easily causes the electrolyte to lose water. The water loss of the battery easily makes it difficult to maintain the dynamic balance of the electrodeposition of manganese oxide reaction inside the battery, and the generation of hydrogen causes the battery to bloat and fail, which in turn causes the battery performance to further decline. In the related art, an open battery can be made to allow the generated hydrogen to escape from the battery to avoid battery bloating. However, the disadvantage of this method is that it accelerates the loss of water. Summary of the invention

[0004] The main purpose of the present invention is to provide an electrodeposited manganese oxide battery to solve the technical problem of battery performance degradation caused by water loss in the electrolyte.

[0005] To achieve the above object, the present invention provides an electrodeposited manganese oxide battery, the electrodeposited manganese oxide battery comprising an electrolyte, the electrolyte comprising a manganese source and an additive; the additive comprising a metal compound and / or a hygroscopic agent.

[0006] In some embodiments of the present invention, the metal compound includes metal oxides and / or metal salts.

[0007] In some embodiments of the present invention, the metal oxide includes a manganese-containing oxide, and the manganese-containing oxide decomposes to generate manganese ions.

[0008] In some embodiments of the present invention, the metal compound includes a metal oxide, the electrodeposited manganese oxide battery includes a negative electrode, the negative electrode includes a metal material, and the type of the metal material is the same as the type of the metal element in the metal oxide.

[0009] In some embodiments of the present invention, the hygroscopic agent comprises a water-locking salt.

[0010] In some embodiments of the present invention, the water-locking salt includes at least one of a zinc salt, a calcium salt, a lithium salt and an organic metal salt.

[0011] In some embodiments of the present invention, the electrolyte further includes a solvent, and the solvent includes an organic solvent and / or an ionic liquid.

[0012] In some embodiments of the present invention, the electrodeposited manganese oxide battery further comprises a positive electrode.

[0013] In some embodiments of the present invention, the positive electrode comprises a material doped with the MnO2;

[0014] And / or, the surface of the positive electrode has a porous structure.

[0015] In some embodiments of the present invention, the manganese ions in the electrolyte are saturated.

[0016] The beneficial effects that can be achieved by the present invention are:

[0017] When the battery is powered on to electrodeposit manganese oxide, the metal salt, manganese salt and water in the electrolyte react to generate MnO2, reduced metal and acid. MnO2 is deposited on the surface of the electrode, and the acid easily reacts with the reduced metal to generate hydrogen, which is also easily precipitated during the subsequent charging process. This will not only lead to the loss of water in the electrolyte, but the production of hydrogen will also easily cause the battery to swell.

[0018] Therefore, the present invention adds a metal compound and / or a hygroscopic agent to the electrolyte, and by replenishing the water lost in the electrolyte during the electrodeposition of manganese oxide, a dynamic balance is achieved inside the battery, thereby alleviating the problem of battery failure due to bloating and achieving the purpose of improving battery performance.

[0019] Among them, the additive metal compound in the electrolyte of the present invention can combine with the hydrogen ions in the acid to generate water, which can not only inhibit the reaction of the reduced metal and the acid to produce hydrogen, but also replenish the water lost in the electrolyte, so that the battery reaches a dynamic balance inside, alleviates the problem of battery failure due to bloating, and achieves the purpose of improving battery performance. The desiccant has the function of absorbing moisture and locking water, and can absorb moisture in the air into the electrolyte, replenish the water lost in the electrolyte during the electrodeposition of manganese oxide, so that the battery reaches a dynamic balance inside, alleviates the problem of battery failure due to bloating, and achieves the purpose of improving battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0021] Figure 1 FIG. 1 is a schematic diagram of the reaction of electrodeposition of manganese oxide according to the present invention.

[0022] Figure 2 This is a performance test diagram of Example 1 of the present invention.

[0023] Figure 3 This is a performance test diagram of Example 2 of the present invention.

[0024] Figure 4 This is a performance test diagram of Example 3 of the present invention.

[0025] Figure 5 This is a performance test diagram of Example 4 of the present invention.

[0026] Figure 6 This is a performance test diagram of Example 5 of the present invention.

[0027] Figure 7 This is a performance test diagram of Example 6 of the present invention.

[0028] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] The invention provides an electrodeposited manganese oxide battery. The electrodeposited manganese oxide battery comprises an electrolyte. The electrolyte comprises a manganese source and an additive. The additive comprises a metal compound and / or a hygroscopic agent.

[0033] It can be understood that the additive includes a metal compound and / or a hygroscopic agent, which means that the additive can be a metal compound, a hygroscopic agent, or a metal compound and a hygroscopic agent.

[0034] In the electrodeposited manganese oxide battery, the electrolyte usually contains a manganese source to provide raw materials for depositing MnO2. The manganese source includes manganese sulfate, manganese dioxide, manganese tetraoxide and other manganese-containing compounds commonly used in the art for depositing manganese dioxide by electroplating. In the present invention, the manganese source in the electrolyte can be provided by conventional electrolyte materials or additives. For example, when the metal compound contains manganese element, no additional electrolyte material for providing the manganese source is required.

[0035] In the present invention, the electrodeposition manganese oxide battery refers to a battery in which the electrolyte can realize Mn on the cathode surface during the charge and discharge process of the battery. 2+ A type of battery that works by the process of MnO2 deposition-dissolution.

[0036] In the process of electrodeposition of manganese oxide, that is, the process of electrolyte reaction after the battery is powered on, the metal salt, manganese salt and water in the electrolyte will react to generate MnO2, reduced metal and acid. MnO2 is deposited on the electrode surface of the battery. The reaction equation is as follows: Figure 1 As shown, X in the equation refers to anions, including Cl - 、SO4 - OH - etc., M represents cation, such as Cd 2 + , Pb 2+ 、Bi 3+ 、Al 3+ 、Zn 2+ Mg 2+The acid generated in the above reaction process is easy to react with the reduced metal to generate hydrogen, and hydrogen will be precipitated during the subsequent charging process, which will not only lead to the problem of reduced water content in the electrolyte, but also face the problem of battery bloating and failure.

[0037] Therefore, the present invention adds additives to the electrolyte, and the additives include metal compounds and / or desiccant. The added metal compounds replenish the water lost by the electrolyte during the electrodeposition of manganese oxide by consuming hydrogen ions in the acid to produce water, and the desiccant replenishes the water lost by the electrolyte during the electrodeposition of manganese oxide by absorbing water, so that the battery reaches a dynamic balance inside, alleviates the problem of battery failure due to bloating, and achieves the purpose of improving battery performance.

[0038] The metal compound combines with the hydrogen ions in the acid to generate water, which can make up for the reduced water content in the electrolyte, so that the battery reaches a dynamic balance inside, alleviates the problem of battery failure due to bloating, and achieves the purpose of improving battery performance. This solution is applicable to both closed batteries and open batteries.

[0039] A closed battery can be understood as a battery with a sealed shell that cannot be opened, and moisture and gas cannot enter. An open battery can be understood as a battery with an opening in the shell, which facilitates the replenishment or maintenance of the internal electrolyte.

[0040] In some embodiments, the metal compound includes a metal oxide and / or a metal salt. It is understood that the metal compound may include a metal oxide, a metal salt, or both a metal oxide and a metal salt.

[0041] Metal oxides contain oxygen atoms, which can combine with hydrogen ions to generate water, replenishing the water lost in the electrolyte. Moreover, metal oxides can further improve the performance of the battery. In addition, electrodeposition of manganese oxide can be understood as the initial charging process, that is, the formation reaction. After the formation is completed, the MnO2 at the positive electrode can be further converted into an intercalation reaction. By adding metal oxides or reduced metals in advance, the generated acid is consumed, which is beneficial to Figure 1 The reaction equation is shifted to the right, which means that the chemical reaction can be better achieved.

[0042] In some embodiments, the metal oxide includes a manganese-containing oxide, which can not only generate water by reacting with hydrogen to replenish the water lost in the electrolyte, but also serve as a source of manganese in the reaction of depositing MnO2.

[0043] In some embodiments, the manganese-containing oxide includes MnO. In this embodiment, MnO is easy to combine with hydrogen ions to generate water, and can also serve as a source of manganese in the reaction of depositing MnO2.

[0044] In some embodiments, the electrodeposited manganese oxide battery further includes a negative electrode, and the material of the negative electrode includes a metal material or a carbon material, and the metal material includes Zn, Cd, Cu, Fe, Pb, Bi or Mn, etc.

[0045] In some embodiments, when the electrolyte of the electrodeposited manganese oxide battery contains metal oxide, the negative electrode is a metal material, and the type of the metal material is the same as the type of the metal element in the metal oxide, the electroplating of MnO2 can be promoted.

[0046] For example, when the metal element in the metal oxide is Zn, the negative electrode is Zn; when the metal element in the metal oxide is Cd, the negative electrode is Cd; when the metal element in the metal oxide is Cu, the negative electrode is Cu; when the metal element in the metal oxide is Fe, the negative electrode is Fe; when the metal element in the metal oxide is Pb, the negative electrode is Pb; when the metal element in the metal oxide is Bi, the negative electrode is Bi; when the metal element in the metal oxide is Mn, the negative electrode is Mn. The type of the metal element in the metal oxide and the type of the metal material of the negative electrode are the same, which can promote the electroplating of MnO2.

[0047] Adding a desiccant to the electrolyte can absorb moisture from the air, make up for the reduced moisture in the electrolyte, and achieve a dynamic balance inside the battery, thereby alleviating the problem of battery failure due to bloating, and achieving the purpose of improving battery performance. This solution is suitable for open batteries.

[0048] In some embodiments, the hygroscopic agent includes a water-locking salt, which can absorb moisture from the air, replenish the moisture lost in the electrolyte, and promote a dynamic balance inside the battery.

[0049] In some embodiments, the water-locking salt includes at least one of zinc salt, calcium salt, lithium salt and organic metal salt. The above types of water-locking salts can effectively absorb and lock the moisture in the air, so as to replenish the water lost in the electrolyte, balance the battery, and alleviate the problem of flatulence in the battery, thereby improving the battery performance.

[0050] In a battery, the electrolyte generally further includes a solvent. In some embodiments, the solvent includes an organic solvent and / or an ionic liquid.

[0051] In the present invention, the desiccant of the present invention also includes a solvent, and the solvent has a hygroscopic function. It can be understood that the solvent in the electrolyte can not only play the function of dissolving the solute, but also play the function of the desiccant to absorb and lock the moisture in the air and replenish the moisture lost in the electrolyte.

[0052] In some embodiments, the desiccant includes ethylene glycol, which can act as a solvent to dissolve solutes in the electrolyte and also act as a desiccant to absorb and lock moisture in the air and replenish the moisture lost in the electrolyte.

[0053] In some embodiments, the solvent includes a eutectic agent, and the eutectic agent includes urea and choline, wherein urea can be used as a hydrogen bond donor, and choline can be used as a hydrogen bond acceptor. The eutectic obtained after deep eutectic of the two has a water absorption function, and can be used as a desiccant to absorb and lock moisture in the air and replenish the moisture lost in the electrolyte. In this embodiment, the cosolvent is one of the ionic liquids.

[0054] In some embodiments, the electrodeposited manganese oxide battery further includes a positive electrode, which includes a metal material or a carbon material. After the battery is powered on, the electrolyte reacts to deposit MnO2 on the surface of the positive electrode.

[0055] In some embodiments, the positive electrode includes a material doped with MnO2. For example, MnO2 is doped in a carbon material, or MnO2 is doped in a metal material. The positive electrode is doped with MnO2 before depositing MnO2, which is beneficial to improving the performance of the battery.

[0056] In some embodiments, the surface of the positive electrode has a porous structure, which is conducive to depositing more MnO2 and improving the performance of the battery.

[0057] In some embodiments, the manganese ions in the electrolyte are saturated, which is beneficial to the deposition of MnO2.

[0058] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention, and are not used to limit the present invention.

[0059] Example 1

[0060] Experimental Group

[0061] The experimental group used carbon materials as positive electrodes and carbon materials as negative electrodes. The electrolyte consisted of 2m ZnCl2 and 3m MnCl2, and ZnO was added to the electrolyte as an additive at an amount of 0.2g / ml. After power was turned on, ZnCl2, MnCl2 and water in the electrolyte would react to generate MnO2, reduced metals and acids.

[0062] Control group

[0063] The control group assembled a battery referring to the experimental group, except that the control group did not add ZnO to the electrolyte.

[0064] Performance Testing

[0065] The batteries in the experimental group and the control group were charged with a fixed current of 2mA for 1mAh, discharged to 0V for 5 cycles, and then charged with a fixed current of 2mAh, discharged to 0V for 5 cycles. The results are shown in Figure 2 , Figure 2 2m ZnCl2+3m MnCl2+ZnO in the formula refers to Example 1, Figure 2 The 2m ZnCl2+3m MnCl2 refers to the control group 1.

[0066] Depend on Figure 2 It can be seen that the metal oxide ZnO was added to the electrolyte of the experimental group. ZnO can combine with hydrogen ions to generate water, replenish the water lost in the electrolyte, promote the dynamic balance of the electrolytic deposition of MnO2 reaction, alleviate the problem of battery gas production failure, and improve the battery cycle performance. The control group 1 did not add ZnO to the electrolyte, and the battery cycle performance was poor.

[0067] Example 2

[0068] Experimental Group

[0069] The experimental group used carbon materials as positive electrodes and carbon materials as negative electrodes. The electrolyte consisted of 2m ZnCl2 and 3m MnCl2, and ZnO was added to the electrolyte as an additive at an amount of 0.2g / ml. After power was turned on, ZnCl2, MnCl2 and water in the electrolyte would react to generate MnO2, reduced metals and acids.

[0070] Control group

[0071] The batteries in the control group were assembled in the same way as the batteries in the experimental group, but the difference was that the carbon negative electrode in the batteries in the control group was replaced with a metal zinc electrode.

[0072] Performance Testing

[0073] The batteries in the experimental group and the control group were charged with a fixed current of 2mA for 1mAh, discharged to 0V for 5 cycles, and then charged with 2mAh, discharged to 0V for 3 cycles, and then charged with 3mAh, discharged to 0V for 3 cycles, and then charged with 4mAh, and discharged to 0V for 3 cycles. The results are shown in Figure 3 , Figure 3 CC in the table refers to the experimental group, and C-Zn refers to the control group.

[0074] Depend on Figure 3 It can be seen that replacing the carbon electrode with a metal zinc electrode has little effect on the cycle performance of the battery, which means that the negative electrode can be either a carbon electrode or a metal zinc electrode, and the addition of ZnO promotes the process of electroplating MnO2.

[0075] Example 3

[0076] Experimental Group

[0077] The experimental group used carbon material as the positive electrode and carbon material as the negative electrode, the electrolyte was 12.5m ZnCl2, and metal oxide MnO was added to the electrolyte with an addition amount of 0.05g / ml.

[0078] Control group

[0079] The battery of the control group was assembled with reference to the battery of the experimental group, except that the metal oxide MnO was not added to the electrolyte in the control group.

[0080] Performance Testing

[0081] The cycle performance of the batteries of Example 3 and Control Group 3 was measured. The results are shown in Figure 4 , Figure 4 The 5m ZnCl2+MnO refers to the experimental group, and the 12.5m ZnCl2 refers to the control group.

[0082] Depend on Figure 4 It can be seen that the experimental group added metal oxide MnO. The addition of metal oxide MnO introduced Mn into the battery. 2+ The metal oxide MnO can react with hydrogen ions to generate water, which replenishes the water lost in the electrolyte during the electrodeposition of manganese oxide, alleviates the problem of battery bloating and failure, and greatly improves the performance of the battery. 2+ source, unable to electrodeposit manganese oxide, from Figure 4 From the results, we can see that the battery performance of control group 3 is very poor.

[0083] Example 4

[0084] Experimental Group

[0085] The experimental group used carbon material as the positive electrode and carbon material as the negative electrode, and the electrolyte contained 0.5mMnCl2 and 13m ZnCl2.

[0086] Control group 1

[0087] The control group 1 assembled a battery with reference to the experimental group, except that the electrolyte of the control group 1 contained only 13mZnCl2.

[0088] Control group 2

[0089] The control group 2 assembled a battery with reference to the experimental group, except that the electrolyte of the control group 1 contained only 0.5 mMnCl2.

[0090] Performance Testing

[0091] The cycle performance of the batteries of Example 3 and Control Group 3 was measured. The results are shown in Figure 5 .

[0092] Figure 5 The left side of the figure shows the water absorption and dehydration of three groups of batteries. MnCl2+ZnCl2 represents the experimental group, ZnCl2 represents the control group 1, and MnCl2 represents the control group 2. From the figure on the left, we can see that under the condition of 60% humidity, the electrolyte of 0.5m MnCl2 (i.e. control group 2) loses water seriously. After adding the water-locking zinc salt ZnCl2 (i.e. the experimental group), it turns to absorb a lot of water, which shows that even at lower humidity, the addition of water-locking salt can inhibit the loss of water.

[0093] Figure 5 The right side of the middle is a comparison chart of the cycle performance of three groups of batteries. The positive and negative electrodes of the three groups of batteries are carbon electrodes. MnCl2+ZnCl2 represents the experimental group, ZnCl2 represents the control group 1, and MnCl2 represents the control group 2. Figure 5 From the figure on the right, we can see that the experimental group with added water-locking salts, that is, the battery containing 13m ZnCl2+0.5m MnCl2 components in the electrolyte, has the best cycle performance. This is because the experimental group contains both manganese salts and zinc salts. Even if there is no ion source at the positive and negative electrodes, electrodeposition of manganese oxide can still be achieved. Moreover, the addition of manganese salts and zinc salts enables the electrolyte to acquire water absorption properties, which can replenish the water lost in the electrolyte during the electrodeposition of manganese oxide, alleviate the problem of battery failure due to bloating, and greatly improve the battery performance.

[0094] Example 5

[0095] Experimental Group

[0096] The experimental group used carbon material as the positive electrode and carbon material as the negative electrode, and the electrolyte contained 13m ZnCl2+0.5m MnCl2.

[0097] Control group 1

[0098] Control group 1 used carbon material as the positive electrode, Zn as the negative electrode, and the electrolyte contained 13m ZnCl2+0.5mMnCl2.

[0099] Control group 2

[0100] Control group 2 used MnO2 as the positive electrode, carbon material as the negative electrode, and the electrolyte contained 13m ZnCl2+0.5m MnCl2.

[0101] Performance Testing

[0102] The cycle performance of three groups of batteries was measured and the results are shown in Figure 6 , Figure 6 CC refers to the experimental group, C-Zn refers to the control group 1, and C-Mn refers to the control group 2.

[0103] Depend on Figure 6 It can be seen that the battery cycle performance of the control group 2, that is, the C-Mn electrode composition is better. In this experiment, the carbon electrode on one side is replaced, that is, the carbon of the positive electrode is replaced with MnO2, and the carbon of the negative electrode is replaced with Zn to further prove the effects of zinc plating and manganese plating on device performance.

[0104] Example 6

[0105] Experimental Group

[0106] The battery's electrolyte consists of urea, choline and 2M manganese acetate (MnAc2).

[0107] Control group

[0108] The electrolyte of the battery is 2M MnAc2.

[0109] Performance Testing

[0110] Example 6 mainly measures the water absorption and dehydration of the electrolytes of the two groups of batteries, so the types of electrodes of the batteries in the experimental group and the control group are not limited. Figure 7 , Figure 7 The 2m MnAc2 in the figure refers to the control group, and urea+choline+MnAc2 refers to the experimental group.

[0111] Depend on Figure 7 It can be seen that under the condition of 60% humidity, the electrolyte of pure MnAc2 in the control group suffered from serious water loss. When the experimental group added eutectic agents urea and choline on the basis of the control group, the water in the electrolyte not only would not be lost, but also could absorb water in the air, greatly improving the water locking performance of the electrolyte when using MnAc2 as the manganese salt for electrodeposition of manganese oxide.

[0112] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An electrodeposited manganese oxide battery, characterized in that: The electrodeposited manganese oxide battery comprises an electrolyte, wherein the electrolyte comprises a manganese source and an additive; the additive comprises a metal compound and / or a hygroscopic agent.

2. The electrodeposited manganese oxide battery according to claim 1, characterized in that: The metal compound includes metal oxides and / or metal salts.

3. The electrodeposition manganese oxide battery according to claim 2, characterized in that: The metal oxide includes a manganese-containing oxide, and the manganese-containing oxide decomposes to generate manganese ions.

4. The electrodeposition manganese oxide battery according to claim 2, characterized in that: The metal compound includes a metal oxide, the electrodeposited manganese oxide battery includes a negative electrode, the negative electrode includes a metal material, and the type of the metal material is the same as the type of the metal element in the metal oxide.

5. The electrodeposited manganese oxide battery according to claim 1, characterized in that: The hygroscopic agent includes water-locking salts.

6. The electrodeposition manganese oxide battery according to claim 5, characterized in that: The water-locking salt includes at least one of zinc salt, calcium salt, lithium salt and organic metal salt.

7. The electrodeposition manganese oxide battery according to claim 1, characterized in that: The electrolyte further includes a solvent, and the solvent includes an organic solvent and / or an ionic liquid.

8. The electrodeposited manganese oxide battery according to any one of claims 1 to 7, characterized in that: The electrodeposited manganese oxide cell also includes a positive electrode.

9. The electrodeposition manganese oxide battery according to claim 8, characterized in that: The positive electrode comprises a material doped with the MnO2; And / or, the surface of the positive electrode has a porous structure.

10. The electrodeposited manganese oxide battery according to claim 1, characterized in that: The manganese ions in the electrolyte are in a saturated state.

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