Patent Application
20190355982
The present invention relates a structure of electrode, and more particularly, to a negative electrode having three-dimensional porous structure and capacitor layer, and a thin battery using the negative electrode as well as a method for making the same.
With the great advance of the smart portable device, a booming development of the wearable devices, such as smart watch, smart glasses, wearable medical care product, and devices for managing sport and health, for example, are also well noticed. Since the wearable devices can be carried by user, the specification of power module for providing required power is strictly limited. In addition to light and thin characteristics as well as the high capacity of power storage, the safety of power module is also an important issue in the application of wearable devices.
Conventionally, a button cell lithium ion (Li-ion) battery still occupies a majority to provide the power for the most part of portable or wearable devices. Since a separation membrane is necessary during manufacturing the button cell Li-ion battery, and an effective package structure is necessary for preventing the liquid electrolyte from leakage, conventionally, the thickness of such kind of battery is more than several millimeters such that it is still difficult to reduce the thickness thereof. In addition, even if there has leakage-proof measure within the button cell lithium ion battery, when the button cell battery has long-time utilization, the leakage of liquid electrolyte may be easily occurred. The liquid electrolyte is poisonous toward the environment and human body, and even worse, there might be a possibility to that the leaked electrolyte is burst into flame or explosion that may endanger the user.
In order to solve the above-mentioned power requirement issue, a solid-state battery is developed. In the solid-state lithium battery, a solid-state electrolyte replaces the conventional liquid electrolyte. A new generation of lithium ion battery is formed by multilayer films. However, conventionally, the films are made of powder material with assistance of binder, and coating process is a conventional way for making the multilayer films of the solid-state battery; therefore, battery miniaturization for the micro scale application still has many limitations. For example, the China published application NO. CN10645028 and CN106941172, or Taiwan issued patent No. 1263702 are related to a technology for making the negative electrode by using powder material. Although the material for making the negative electrode may be similar, there has technical limitation on the requirement of miniaturization and thinness. Therefore, the conventional arts are not suitable for the device utilized in the micro scale application.
Accordingly, there has a need for developing a totally new negative electrode, and method for making the same and a thin battery using the negative electrode so as to improve the power capability of the micro scale devices thereby expanding the utilization in various application fields.
Embodiments of the present invention provide a thin film negative electrode of lithium ion battery on a current collector, in which the negative electrode has a three-dimensional porous structure for increasing contact area between the negative electrode and the electrolyte thereby reducing the diffusion path of the lithium ions. In addition, the three-dimensional porous structure of negative electrode is made from highly stable metal oxide, for example, titanium oxide or vanadium oxide; therefore, it can prevent the structure of the electrode from being damaged during the charge-discharge process thereby enhancing the charge-discharge stability of the battery.
Embodiments of the present invention provide a negative electrode and a thin film battery using the negative electrode. Since the negative electrode is a thin-film electrode, it can be adapted in the micro scale device, thereby reducing the thickness and bulk volume of the micro scale device.
In one embodiment, the negative electrode and thin-film battery comprise a three-dimensional porous structure made by titanium oxide and a capacitor layer formed on the porous structure, whereby the structure strength of the negative electrode and battery can be greatly improved. In order to make a thin film battery, the titanium film is etched for forming a frame structure having three-dimensional porous frame and the capacitor layer is subsequently deposited on the three-dimensional porous frame structure so that a negative electrode and thin film battery having better structure strength, high porosity, more flexibility and superior charge-discharge stability can be obtained.
One embodiment of the present invention provides a negative electrode of a thin film battery comprising a porous structural layer, a capacitor layer, and a lithium ion source layer. The porous structural layer is formed on a metal substrate, wherein the thickness of the porous structural layer is between 200 nm-700 nm. The capacitor layer is formed on the porous structural layer, wherein the thickness of the capacitor layer is between 100 nm-300 nm. The lithium ion source layer is formed on the capacitor layer.
One embodiment of the present invention provides a method for making a negative electrode of a thin film battery, comprising steps of providing a metal substrate, forming a structural layer on the metal substrate, transforming the structural layer into a porous structural layer, forming a capacitor layer on the porous structural layer, and forming a lithium ion source layer on the capacitor layer. In one embodiment, the thickness of the porous structural layer is between 200 nm-700 nm.
One embodiment of the present invention provides a thin film battery, comprising a positive electrode, and a negative electrode, wherein the negative electrode is coupled to the positive electrode, and the negative electrode further comprises a porous structural layer, a capacitor layer and a lithium ion source layer. The porous structural layer is formed on a first metal substrate. The capacitor layer is formed on the porous structural layer. The lithium ion source layer is formed on the capacitor layer. In one embodiment, the thickness of the porous structural layer is between 200 nm-700 nm, and the thickness of the capacitor layer is between 100 nm-300 nm.
One embodiment of the porous structural layer comprises a metal oxide, wherein the metal oxide is titanium oxide or vanadium oxide, and a material formed the capacitor layer is silicon. The porous structural layer comprises a plurality of nano scale void spaces, and the porosity is between 75%˜90%. The porous structural layer comprises a metal oxide formed by oxidizing a metal layer formed on a surface of the metal substrate through a sputtering process.
In one embodiment, a capacitor material of the capacitor layer is formed on the porous structural layer through a sputtering process.
In one embodiment, a solid-state organic electrolyte layer the lithium ion source layer. Alternatively, an oxidation layer is further formed on the solid-state organic electrolyte layer.
Embodiments of the present invention will now be specified with reference to the drawings, in which:
The invention disclosed herein is directed to a negative electrode of thin film battery and method for making the same and a thin film battery using the negative electrode. In the following description, numerous details are set forth in order to provide a thorough understanding of the present invention. It will be appreciated by one skilled in the art that variations of these specific details are possible while still achieving the results of the present invention. In other instance, well-known components are not described in detail in order not to unnecessarily obscure the present invention.
Please refer to
The porous structural layer 201 is formed on the metal substrate 200. The thickness of the porous structural layer 201 is about 200 nm-700 nm. In one embodiment, the thickness of the porous structural layer 201 is between 500 nm-700 nm, but it is not be limited thereto. The base material for forming the porous structural layer 201 is titanium or vanadium. In the present embodiment, titanium is used as the base material for making the porous structural layer 201.
In one embodiment, the porous structural layer 201 is formed by the steps of forming a metal layer on the metal substrate 200, converting the metal layer into the porous structural layer 201 having a three-dimensional structure through a chemical treatment. For example, in
The capacitor layer 202 is formed on the porous structural layer 201. In one embodiment, the thickness of the capacitor layer 202 is around 100 nm-300 nm, but it is not be limited thereto. Regarding the material forming the capacitor layer 202, please refer to the
The lithium ion source layer 203 is formed on the capacitor layer 202. In one embodiment, the material for forming lithium ion source layer is lithium source which may be, but is not limited to, LiClO4, LiCF3SO3, LiPF6, LiN(SO2CF3)2, Li2SO4, LiNO3, LiF, Li2CO3, or LiBF4. In the present embodiment, the material is LiClO4. In one embodiment, a solid-state organic electrolyte layer 204 is further formed on the lithium ion source layer 203. In one embodiment, porphyrin material is formed as the solid-state organic electrolyte layer 204 on the lithium ion source layer 203 through a vacuum evaporation procedure. Alternatively, in addition to porphyrin, the solid-state organic electrolyte layer 204 can also be formed by material of porphyrin, N-confused tetraphenylporphyrin (NCTPP), corrin, or chlorine.
When the porphyrin is utilized as the solid-state organic electrolyte layer 204, the temperature range of charging-discharging reaction of the negative electrode in the thin film battery can be increased, especially for the environment under extremely low temperature. For example, the battery can still be operated when the environmental temperature comes to −45° C. On the other hand, the solid-state organic electrolyte material having the porphyrin can also reduce the diffusion time of the lithium ions thereby increasing the charging speed. Alternatively, an oxidation layer 205 can be formed on the solid-state organic electrolyte layer 204, wherein the material of the oxidation layer 205 may be, but is not be limited to, silicon dioxide.
It is noted that, the characteristic of the above-mentioned embodiments is that the negative electrode 20 comprises a super thin three-dimensional porous structure on a current collector, whereby the three-dimensional frame structure with a plurality of void spaces can increase contacting area between the porous structure and electrolyte so as to shorten the diffusion path of the lithium ions. In case of titanium dioxide, since titanium has advantage of stability, when the porous structural layer is made from the titanium, the issues of charging-discharging instability due to the damage of negative electrode caused by volume expansion during the charging-discharging process of the capacitor layer can be greatly improved.
Please refer to
The lithium oxide layer 211 is formed on the metal material layer 210, which may be formed by a lithium included material such as LiCoO2, LiMn2O4, LiNiO2, or LiFePO4, for example. Alternatively, the lithium oxide layer 211 can also be LiNixCo1-xO2, or LiNixCoyMn1-x-yO2. It is noted that there has no specific limitation about the material forming the lithium oxide layer 211, and the material for forming the lithium oxide layer 211 can be determined according to the user's need. The solid-state organic electrolyte layer 212 is formed on the lithium oxide layer 211.
The material for forming the solid-state organic electrolyte layer 212 is porphyrin, which is formed on the lithium oxide layer 211 through a vacuum evaporation. In addition to the vacuum evaporation, other alternatives, such as immersion, roll coating, spray coating, or brush coating can be utilized to form the solid-state organic electrolyte layer 212. The solid-state organic electrolyte layer 212 can increase the reaction temperature range, especially environment under extremely low temperature. In one embodiment, the low temperature can reach −45° C. The thin film battery 2 further comprises an oxide layer 213 and/or 205 between the positive and negative electrodes 20 and 21. The oxide layer 213 and/or 205 can be an isolation layer between the positive and negative electrodes 20 and 21. In one embodiment, the oxide layer 213 or 205 or the combination of 203 and 205 may be, but is not limited to, silicon dioxide. Alternatively, a lithium ion source layer is further formed between the solid-state organic electrolyte layer 212 and the lithium oxide layer 211, wherein the lithium ion source layer, in one embodiment, is formed on the lithium oxide layer 211 through a wet coating process.
Please refer to
It is noted that it is not limited to single metal layer formed on the carrier. Alternatively, it is available to form multiple metal layers on the carrier. In addition to using the adhesive layer as carrier, a glass substrate can also be utilized as the carrier. Next, a step 42 is performed to form a metal layer on the metal substrate. In the present step 42, a cleaning step for washing the metal substrate and carrier and a drying step for drying the washed metal substrate and carrier can be performed before forming the metal layer on the metal substrate. In one embodiment, a sputtering manufacturing process, such as magnetron sputtering, is utilized for forming the metal layer having a specific thickness on the metal substrate. In addition to the sputtering process, the evaporation or electroplating process can also be an alternative way as well. The material of the metal layer can be titanium. Alternatively, the vanadium or the like can also be selected.
Next a step 43 is performed for transforming the metal layer into a porous structural layer through a chemical treatment. The chemical treatment here in the present embodiment is heat-alkaline treatment. In the heat-alkaline treatment, an alkaline solution is utilized to etch the metal layer whereby a plurality of void spaces with nanometer dimension can be formed on the metal layer. In one embodiment, the alkaline solution is 5M NaOH solution. It is noted that the alkaline solution can be chosen according to the user's need, and it is not limited to the previously described example.
After etching the metal layer, the whole carrier is performed a hydrothermal reaction in the furnace for 0.5-2 hours. In one embodiment, the reaction temperature of the hydrothermal reaction may be, but is not be limited to, 80° C. In addition, the reaction time depends on the user's need and there has no specific limitation. After the hydrothermal reaction, deionized water is utilized to wash the product of the hydrothermal reaction. Finally, the alcohol is utilized to wash the carrier and the porous structure. After that, a gas is utilized to dry the carrier and the porous structure. In one embodiment, the dry process can be implemented by a nitrogen gun. After drying the product, a further drying step operated in the dry box at 50° C. for a period of time can be performed. It is noted that, the washing and drying steps are not necessary steps which depends on the user's need.
After the porous structural layer is completely formed, a step 44 is operated to form a capacitor layer on the porous structural layer. In the present embodiment, a magnetron sputtering process is utilized to form the capacitor layer having thickness of 100 nm-300 nm on the porous structural layer. The material for forming the capacitor layer can be selected from the material shown in
After step 46, a step 47 is performed to form an oxide layer on the solid-state organic electrolyte layer. In one embodiment, a silicon dioxide layer is formed on the solid-state organic electrolyte layer by the magnetron sputtering process or E-dun process. Finally, step 48 is performed for removing the carrier from the metal substrate. In one embodiment of step 48, the carrier can be immersed into to an organic solution, such as acetone (CH3COCH3), for example, for eliminating the adhesive layer whereby the carrier can be removed from metal substrate. After removing the carrier from the metal substrate, the residual adhesive layer on the metal substrate can be further removed so as to form a negative electrode having porous structural layer formed on the copper foil.
Please refer to
It is noted that since proper manufacturing conditions are necessary to be maintained for forming the metal layer when sputtering manufacturing process is utilized, the roll-to-roll apparatus 7 can be arranged in a chamber of a housing 73 having manufacturing devices 75, such as sputtering device, or evaporation device, for example, arranged therein. Because the coating conditions can be easily controlled, coating procedure can be smoothly performed under the various kinds of coating conditions controlled in the chamber. Alternatively,
After the step 41a, a step 42a is operated to perform a chemical reaction for treating the metal layer formed on a surface of the metal substrate in the step 41a whereby the metal layer is converted into a porous structural layer. It is noted that the roll-to-roll apparatus shown in
Next, a step 43a is further performed to form a capacitor layer on the porous structural layer through the roll-to-roll process. It is noted that the roll-to-roll apparatus shown in
Next, a step 45a is operated for forming a solid-state organic electrolyte layer on the lithium ion source layer. Similarly, the roll-to-roll manufacturing process is operated in step 45a. It is noted that the roll-to-roll apparatus shown in
Next, a step 46a is further processed to form an oxide layer on the solid-state organic electrolyte layer through the roll-to-roll process. It is noted that the roll-to-roll apparatus shown in
Alternatively, a step of combining positive electrode on the metal roll can be performed between the steps 46a and 47a. It is noted that, in one embodiment, the positive electrodes are also formed on another metal roll; therefore, the step of combining positive electrode with the negative electrode can be performed by combing the two metal rolls together through a hot pressing procedure. Alternatively, a series of film-coating steps for forming the positive electrode can be performed between the steps 46a and 47a for eliminating the hot pressing assembly procedure.
Please refer to
After the step 50, a step 51 of forming positive electrode is performed. In the step 51, it further comprises a first step of providing a metal substrate arranged or removably attached on a carrier, which may be, but is not limited to a glass or adhesive layer. Next a second step for subsequently forming lithium oxide layer, a solid-state organic electrolyte layer, and an oxide layer on the metal substrate is proceeded. The metal substrate, in one embodiment, may be, but is not be limited to, an aluminum foil. Other metal material that is suitable for the positive electrode can be utilized. The lithium oxide layer can be material having lithium metal, such as LiCoO2, LiMn2O4, LiNiO2, or LiFePO4, for example. Alternative, the lithium oxide layer can be formed by LiNixCo1-xO2 or LiNixCoyMn1-x-yO2, depending on the user's need without any specific limitation.
The solid-stage organic electrolyte layer is formed on the lithium oxide layer. In the present embodiment, the solid-state organic electrolyte layer is porphyrin, which is formed on the lithium oxide layer through a vacuum evaporation. The solid-state organic electrolyte layer formed by porphyrin can increase the range of reaction temperature of the thin film battery, especially in the environment having extremely low temperature. In one embodiment, the low temperature can reach −45° C. In addition, the porphyrin can also help reduce the diffusion time of lithium ions for increasing the charging speed. The oxide layer is formed on the solid-state organic electrolyte layer. In the present embodiment, the oxide layer is silicon dioxide. Regarding the oxide layer, it is noted that the step 46 shown in
In addition, please refer to
According to the above-mentioned embodiments, it is clear that embodiments of the present invention provide a thin film negative electrode of lithium ion battery on a current collector, in which the negative electrode has a three-dimensional porous structure for increasing contact area between the negative electrode and the electrolyte thereby shortening the diffusion path of the lithium ions. In addition, the three-dimensional porous structure of negative electrode is made from highly stable metal whereby it can prevent the structure of the electrode from being damaged during the charge-discharge process of the battery thereby enhancing the charge-discharge stability of the battery. Since the negative electrode is a thin-film electrode, it can be adapted in the application field required micro scale device, thereby reducing the thickness and bulk volume of the micro scale device.
While embodiments of the present invention have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and detail may be without departing from the spirit and scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 107116923 | May 2018 | TW | national |
