Customized surface electrolyte mesophase

Abstract

A battery includes a separator, a conductive substrate, a negative electrode connected to the conductive substrate, and a surface electrolyte mesophase (SEI) disposed between the separator and the negative electrode. And a surface electrolyte intermediate phase including a first layer coupled to the negative electrode and forming a first interface with the negative electrode and a second layer coupled to the first layer and forming a second interface with the separator, the first layer being made of a first material and the second layer being made of a second material different from the first material.

Description

[0001] introduction

[0002] The information provided in this section is for the purpose of presenting the general context of this disclosure. The work of the currently attributed inventors, to the extent described in this section, and aspects of the description that might not otherwise be considered prior art at the time of filing, are neither expressly nor implicitly acknowledged as prior art to this disclosure. Technical Field

[0003] This disclosure relates generally to electroactive materials, and more specifically to surface electrolyte interphases. Background Technology

[0004] Advanced energy storage devices and systems are needed to meet the energy and / or power requirements of various products, including automotive products such as start-stop systems (e.g., 12V start-stop systems), battery auxiliary systems, hybrid electric vehicles (“HEVs”), and electric vehicles (“EVs”). A typical battery includes at least two electrodes and an electrolyte and / or separator. One of the two electrodes can be used as the positive electrode or cathode, and the other as the negative electrode or anode. A separator filled with a liquid, solid, or semi-solid electrolyte can be disposed between the negative and positive electrodes. The electrolyte is suitable for conducting ions (e.g., lithium ions, calcium ions, sodium ions, and / or potassium ions) between the electrodes and, like the two electrodes, can be in solid and / or liquid form and / or a mixture thereof. In the case of solid-state batteries, which include solid electrodes and a solid electrolyte (or solid separator), the solid electrolyte (or solid separator) can physically separate the electrodes, eliminating the need for separate separators.

[0005] Conventional rechargeable batteries operate by reversibly transferring ions back and forth between a negative electrode and a positive electrode. For example, ions can move from the positive electrode to the negative electrode during battery charging and in the opposite direction when the battery is discharged. Such a battery can reversibly supply power to an associated load device as needed. More specifically, power can be supplied to a load device by the battery until the lithium, calcium, sodium, and / or potassium content at the negative electrode is effectively depleted. The battery can then be recharged by transferring a suitable direct current in the opposite direction between the electrodes.

[0006] During discharge, the negative electrode may contain a relatively high concentration of intercalated lithium, calcium, sodium, and / or potassium, which are oxidized into electron-releasing lithium, calcium, sodium, and / or potassium ions. These lithium, calcium, sodium, and / or potassium ions can travel from the negative electrode to the positive electrode, for example, through an ion-conducting electrolyte solution contained within the pores of an intercalated porous separator. Simultaneously, electrons travel from the negative electrode to the positive electrode via an external circuit. Such lithium, calcium, sodium, and / or potassium ions can be assimilated into the positive electrode material through an electrochemical reduction reaction. The battery can be recharged or regenerated at its usable capacity after partial or complete discharge by an external power source, reversing the electrochemical reactions that occurred during discharge. Summary of the Invention

[0007] In one configuration, a battery is provided, comprising a separator, a conductive substrate, a negative electrode coupled to the conductive substrate, and a surface electrolyte interphase (SEI) disposed between the separator and the negative electrode. The surface electrolyte interphase comprises a first layer and a second layer, the first layer being coupled to the negative electrode and forming a first interface therewith, and the second layer being coupled to the first layer and forming a second interface therewith. The first layer is made of a first material, and the second layer is made of a second material different from the first material.

[0008] A battery may include one or more of the following optional aspects. For example, the separator may contain an electrolyte.

[0009] According to at least one aspect, the battery further includes a third interface between the first layer and the second layer. The first layer may be made of a first film configured to adhere to a portion of the negative electrode, and the second layer may be made of a second film configured to adhere to a portion of the first film. The third interface may include interlocking portions of the first and second layers.

[0010] According to another aspect, the first layer may have a first thickness, and the second layer may have a second thickness that is substantially the same as the first thickness.

[0011] According to at least one example, the first layer may contain inorganic compounds. The second layer may include compounds rich in organic matter.

[0012] According to another example, the first interface may include a first material that is chemically stable relative to the negative electrode, and the second interface may include a second material that is chemically stable relative to the isolate.

[0013] According to at least one aspect, both the first and second layers are formed by a process including in-situ chemical reactions.

[0014] In another configuration, a battery is provided, comprising a separator, a conductive substrate, a negative electrode coupled to the conductive substrate, and a surface electrolyte interphase (SEI) disposed between the separator and the negative electrode. The surface electrolyte interphase includes a first interface with the negative electrode, a second interface with the separator, and a transition region disposed between the first and second interfaces. This transition region includes a first major component of a first material near the first interface and a second major component of a second material near the second interface.

[0015] A battery may include one or more of the following optional aspects. For example, the separator may contain an electrolyte.

[0016] According to at least one aspect, the first material may include an inorganic compound. The second material may include a compound rich in organic matter.

[0017] According to another aspect, the surface electrolyte intermediate phase includes an SEI thickness, and the transition region includes a transition thickness of approximately half the SEI thickness.

[0018] In another configuration, a vehicle is provided, comprising a vehicle body and one or more battery modules coupled to the vehicle body. Each of the one or more battery modules has one or more battery cells, each of the one or more battery cells including a negative electrode, a positive electrode, a separator disposed between the negative electrode and the positive electrode, a first current collector positioned relative to the separator and near the negative electrode, a second current collector positioned relative to the separator and near the positive electrode, and a surface electrolyte interphase (SEI) disposed between the negative electrode and the separator. The surface electrolyte interphase includes a first end and a second end, the first end being arranged adjacent to the negative electrode and forming a first interface with the negative electrode, and the second end being spaced apart from the first end and arranged adjacent to the positive electrode and forming a second interface with the positive electrode. The first interface includes a first major component, and the second interface includes a second major component, the first major component being different from the second major component.

[0019] The vehicle may include one or more of the following optional aspects. For example, the first major component may include an inorganic compound. The second major component may include a compound rich in organic matter.

[0020] According to at least one aspect, the surface electrolyte intermediate phase includes a third interface disposed between a first interface and a second interface, a first layer including a first major component extending between the first interface and the third interface, and a second layer including a second major component extending between the third interface and the second interface.

[0021] According to another aspect, the surface electrolyte intermediate phase includes a transition region disposed between a first end and a second end, and the transition region typically includes equal portions of a first major component and a second major component. Attached Figure Description

[0022] The accompanying drawings described herein are for illustrative purposes only for the selected configurations and are not intended to limit the scope of this disclosure.

[0023] Figure 1 This is a front perspective view of a vehicle including a battery pack connected to a motor, based on the principles of this disclosure.

[0024] Figure 2 It includes one or more battery cells. Figure 1 A perspective view of the battery modules of the battery pack;

[0025] Figure 3 yes Figure 2 A diagram of one of one or more battery cells;

[0026] Figure 4 yes Figure 3 A partial view of the first configuration of the battery cells; and

[0027] Figure 5 yes Figure 3 A partial view of the second configuration of the battery cells.

[0028] In all the accompanying drawings, the corresponding reference numerals denote the corresponding parts. Detailed Implementation

[0029] The example configuration will now be described more fully with reference to the accompanying drawings. The example configuration is provided so that this disclosure will be thorough and will fully communicate the scope of this disclosure to those skilled in the art. Specific details, such as examples of specific components, apparatus, and methods, are set forth to provide a thorough understanding of the configuration of this disclosure. It will be apparent to those skilled in the art that specific details are not required, the example configuration may be embodied in many different forms, and the specific details and example configuration should not be construed as limiting the scope of this disclosure.

[0030] The terminology used herein is for the purpose of describing a particular exemplary configuration only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having” are inclusive and therefore specify the presence of features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0031] When an element or layer is referred to as “on another element or layer,” “joined to,” “connected to,” “attached to,” or “linked to” another element or layer, it may be directly on, joined to, attached to, or linked to the other element or layer, or there may be intermediate elements or layers present. Conversely, when an element is referred to as “directly on another element or layer,” “directly joined to,” “directly connected to,” “directly attached to,” or “directly linked to” another element or layer, there may be no intermediate elements or layers present. Other terms used to describe relationships between elements should be interpreted in a similar manner, such as “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0032] The terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or parts. These elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or part from another. Unless the context clearly indicates otherwise, terms such as “first,” “second,” and other numerical terms do not imply order or sequence. Therefore, without departing from the teachings of the example configuration, the first element, component, region, layer, or part discussed below may be referred to as the second element, component, region, layer, or part.

[0033] In this application, including the following definitions, the term "module" may be replaced by the term "circuit". The term "module" may refer to, be part of, or include the following: application-specific integrated circuit (ASIC); digital, analog, or mixed-signal analog / digital discrete circuit; digital, analog, or mixed-signal analog / digital integrated circuit; combinational logic circuit; field-programmable gate array (FPGA); processor (shared, dedicated, or grouped) for executing code; memory (shared, dedicated, or grouped) for storing code executed by the processor; other suitable hardware components that provide the described functionality; or some or all of the foregoing, such as in a system-on-a-chip.

[0034] The term "code" as used above can include software, firmware, and / or microcode, and can refer to programs, routines, functions, classes, and / or objects. The term "shared processor" covers a single processor that executes some or all of the code from multiple modules. The term "group processor" covers a processor that, in combination with additional processors, executes some or all of the code from one or more modules. The term "shared memory" covers a single memory that stores some or all of the code from multiple modules. The term "group memory" covers memory that, in combination with additional memory, stores some or all of the code from one or more modules. The term "memory" can be a subset of the term "computer-readable medium." The term "computer-readable medium" does not include transient electrical and electromagnetic signals propagating through the medium, and therefore can be considered tangible and non-transitory memory. Non-limiting examples of non-transitory memory include tangible computer-readable media, which include non-volatile memory, magnetic memory, and optical memory.

[0035] The apparatus and methods described in this application can be implemented, partially or entirely, by one or more computer programs executed by one or more processors. The computer program includes processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. The computer program may also include and / or depend on stored data.

[0036] A software application (i.e., a software resource) can refer to computer software that enables a computing device to perform tasks. In some examples, a software application may be referred to as an "application," "app," or "program." Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and game applications.

[0037] Non-transitory memory can be a physical device used to temporarily or permanently store programs (e.g., instruction sequences) or data (e.g., program state information) for use by a computing device. Non-transitory memory can be volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electrically erasable programmable read-only memory (EEPROM) (e.g., commonly used in firmware, such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase-change memory (PCM), and magnetic disks or magnetic tapes.

[0038] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and can be implemented using high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the terms “machine-readable medium” and “computer-readable medium” refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including machine-readable media that receive machine instructions as machine-readable signals. The term “machine-readable signal” refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0039] Various implementations of the systems and techniques described herein can be implemented in digital electronic and / or optical circuits, integrated circuits, specially designed ASICs (Application-Specific Integrated Circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementations in one or more computer programs executable and / or interpretable on a programmable system, which includes at least one programmable processor, which may be dedicated or general-purpose, coupled to receive data and instructions from a storage system, at least one input device, and at least one output device, and to transmit data and instructions to the storage system, at least one input device, and at least one output device.

[0040] The processes and logical flows described in this specification can be executed by one or more programmable processors (also known as data processing hardware) that execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logical flows can also be executed by special-purpose logic circuitry (e.g., FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits)). For example, processors suitable for executing computer programs include both general-purpose and special-purpose microprocessors, as well as any one or more processors of any type of digital computer. Typically, the processor receives instructions and data from read-only memory or random access memory, or both. The basic elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or operatively coupled to receive data from or transfer data to, or both. However, a computer does not need to have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks or removable disks; magneto-optical disks; and CD-ROMs and DVD-ROMs. Processors and memory may be supplemented by or incorporated into dedicated logic circuitry.

[0041] To provide interaction with a user, one or more aspects of this disclosure can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touchscreen) for displaying information to the user and optionally a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback, such as visual, auditory, or tactile feedback; and input from the user can be received in any form, including sound, speech, or tactile input. Additionally, the computer can interact with the user by sending documents to and receiving documents from the device used by the user; for example, by sending a webpage to a web browser on the user's client device in response to a request received from a web browser.

[0042] refer to Figure 1This document provides an illustrative example of a vehicle 10 (such as an electric vehicle). The vehicle 10 includes a body 12, one or more wheels 14, and an electric motor 16 disposed in and / or coupled to the body 12. The electric motor 16 may be configured to drive at least one of the one or more wheels 14 to propel the vehicle 10. The vehicle 10 includes a battery pack 100, which may be disposed in and / or coupled to the body 12 and communicatively coupled to the electric motor 16 via a power cable 18.

[0043] The battery pack 100 may have one or more battery modules 110, each battery module 110 including one or more battery cells 200. Figure 2 One or more battery cells 200 may be prismatic battery cells, such as... Figure 2 As shown. However, the principles of this disclosure are also applicable to other types of battery cells (e.g., pouch cell cells, cylindrical cell cells, etc.). One or more battery cells 200 each include components configured to house internal battery cell components (…). Figure 3 )204's main body 202 (e.g., prismatic can).

[0044] refer to Figure 3 Each of one or more battery cells 200 includes a negative electrode 206 (e.g., anode), a positive electrode 208 (e.g., cathode), and a separator 210 disposed between the negative electrode 206 and the positive electrode 208. The separator 210 provides electrical separation between the electrodes 206, 208—preventing physical contact. During lithium-ion cycling, the separator 210 also provides a path of least resistance for the internal passage of lithium ions (and in some cases, associated anions). The separator 210 can be in solid and / or liquid form and / or a mixture thereof. For example, in some variations, the separator 210 may include an electrolyte 212. In some variations, the separator 210 may be formed of a solid electrolyte or a semi-solid electrolyte (e.g., a gel electrolyte). For example, the separator 210 may include multiple solid electrolyte particles and / or gel electrodes.

[0045] A first current collector 214 (e.g., a negative current collector) may be located at or near a negative electrode (which may also be referred to as a negative conductive substrate) 206. The first current collector 214, together with the negative electrode 206, may be referred to as a negative electrode assembly. Although not shown, in some variations, a layer of negatively active material may be disposed on one or more parallel sides of the first current collector 214. Similarly, in other variations, a layer of negatively active material may be disposed on a first side of the first current collector 214, and a layer of positively active material may be disposed on a second side of the first current collector 214. In each case, the first current collector 214 may be a metal foil, a metal mesh or sieve, or an extended metal comprising copper or any other suitable conductive material known to those skilled in the art.

[0046] A second current collector 216 (e.g., a positive current collector) may be positioned at or near the positive electrode (which may also be referred to as a positive conductive substrate) 208. The second current collector 216, together with the positive electrode 208, may be referred to as a positive electrode assembly. Although not shown, in some variations, a layer of positively active material may be disposed on one or more parallel sides of the second current collector 216. Similarly, in other variations, a layer of positively active material may be disposed on a first side of the second current collector 216, and a layer of negatively active material may be disposed on a second side of the second current collector 216. In each case, the second current collector 216 may be a metal foil, a metal mesh or sieve, or an extended metal comprising aluminum or any other suitable conductive material known to those skilled in the art.

[0047] The first current collector 214 and the second current collector 216 can collect free electrons and move free electrons to and from the external circuit 218, respectively. For example, the interruptible external circuit 218 and the load device 220 can connect the negative electrode 206 (through the first current collector 214) and the positive electrode 208 (through the second current collector 216). The battery 20 can generate current during discharge through a reversible electrochemical reaction that occurs when the external circuit 218 is closed (to connect the negative electrode 206 and the positive electrode 208) and the negative electrode 206 has a lower potential than the positive electrode. The chemical potential difference between the positive electrode 208 and the negative electrode 206 drives electrons generated by the reaction at the negative electrode 206 (e.g., the oxidation of lithium intercalation) towards the positive electrode 208 through the external circuit 40. Similarly, lithium ions generated at the negative electrode 206 are simultaneously transferred towards the positive electrode 208 through the electrolyte 212 contained in the separator 210. Electrons flow through external circuit 218, and lithium ions migrate through separator 210 containing electrolyte 212 to form intercalated lithium at positive electrode 208. Current through external circuit 40 can be utilized and directed through load device 220 until the lithium in negative electrode 206 is depleted and the capacity of one or more battery cells 200 decreases.

[0048] Continue to refer to Figure 3 Each of one or more battery cells 200 may optionally include a cathode electrolyte interphase (CEI) 222 disposed between the separator 210 (i.e., electrolyte 212) and the positive electrode 208. The CEI 222 may be coupled to and / or disposed on the positive electrode 208. For example, the CEI 222 may be desirable to enhance the stability and / or performance of one or more battery cells 200.

[0049] Each of one or more battery cells 200 includes a surface electrolyte interphase (SEI) 224 disposed between a separator 210 (i.e., electrolyte 212) and a negative electrode 206. The SEI 224 is coupled to and / or disposed on the negative electrode 206. For example, the SEI 224 may be coupled to the surface of the negative electrode 206 and / or at least partially embedded in the negative electrode 206. The interaction between the SEI 224 and the negative electrode 206 can be examined, for example, using X-ray photoelectron spectroscopy (XPS) depth profiling. As will be discussed in more detail below, the structure of the SEI 224 can be controlled and / or customized using processes involving in-situ electrochemical reactions. Typically, the SEI 224 is expected to possess high chemical stability, high ionic conductivity, low thickness to reduce ion diffusion resistance, and / or high elastic modulus and mechanical strength to suppress dendrite growth and fracture. To date, SEIs have typically been monolithic, and their components have typically been high in elastic modulus but low in ionic conductivity (e.g., lithium fluoride (LiF)) or high in flexibility but low in elastic modulus (e.g., lithium carboxylate (LiCO2CF3)).

[0050] Figure 4 An illustrative configuration of a battery 300, including multiple layers of SEI 324, is shown. This configuration is similar in many respects to... Figure 1-3 The configuration. Therefore, the descriptions of the configuration are combined here, and it is generally not necessary to repeat descriptions of topics that are common to the configuration.

[0051] refer to Figure 4 A multilayer SEI 324 is disposed between the separator 310 (i.e., electrolyte 312) and the negative electrode 306. In this illustrative example, the multilayer SEI 324 includes a first layer 326 and a second layer 328. The first layer 326 may be coupled to and / or disposed on the negative electrode 306, and the second layer 328 is coupled to and / or disposed on the first layer 326, as shown below. Figure 4 As shown. According to one aspect, the first layer 326 may be at least partially coupled to (i.e., embedded in, interlocked with, etc.) the negative electrode 306, such that the negative electrode 306 is sandwiched between the first layer and the first current collector 314 (e.g., a negative current collector). Additionally or alternatively, the second layer 328 may be at least partially coupled to (i.e., embedded in, interlocked with, etc.) the first layer 326, such that the first layer 326 is sandwiched between the second layer 328 and the negative electrode 306. The first layer 326 may be made of a first film configured to adhere to a portion of the negative electrode 306, and the second layer may be made of a second film configured to adhere to a portion of the first film. The interaction between the first layer 326 and the negative electrode 306 and / or between the first layer 326 and the second layer 328 can be examined using, for example, X-ray photoelectron spectroscopy (XPS) depth profiling.

[0052] According to one aspect, the first layer 326 may have a first thickness T1, and the second layer 328 may have a second thickness T2, and the first thickness T1 and the second thickness T2 together define the thickness T3 of the multilayer SEI 324. The thickness T3 of the multilayer SEI 324 may be between 1 nanometer and 150 nanometers, and preferably between 10 nanometers and 50 nanometers. In this illustrative configuration, the first thickness T1 and the second thickness T2 are substantially the same. However, in at least one example, the first thickness T1 may be thicker or thinner than the second thickness T2.

[0053] Battery 300 includes a first interface 330 between a first layer 326 and a negative electrode 306, and a second interface 332 between a second layer 328 and a separator 310 (i.e., electrolyte 312). Optionally, a third interface 334 may be arranged and defined between the first layer 326 and the second layer 328. The third interface 334 may include a boundary where the first layer 326 ends and the second layer 328 begins. Combining the selection of various electrolytes and / or additives to control the formation protocol (i.e., voltage, current density / rate, additive timing, etc.) may be desirable for forming the first interface 330, the second interface 332, and / or the third interface 334 for a particular purpose. According to at least one aspect, processes involving in-situ chemical reactions can be used to control and / or customize the multilayer SEI 324, more specifically, the first layer 326 and / or the second layer 328. According to another aspect, the first interface 330 may include a first major component, and the second interface 332 may include a second major component. The first major component may be different from the second major component.

[0054] The first layer 326 may be made of a first material, and the second layer 328 may be made of a second material different from the first material. The first material may be a hard or inorganic-rich compound that is chemically stable to the negative electrode material (e.g., lithium metal). For example, the first material may be made of lithium fluoride (LiF) or lithium oxide (Li2O). The second material may be a soft (i.e., flexible) or organic-rich compound that is chemically stable to the separator 310 (i.e., electrolyte 312). For example, the second material may be made of lithium trifluoroacetate (LiCO2CF3). According to one aspect, the first material may be a first major component at the first interface 330, and the second material may be a second major component at the second interface 332.

[0055] Figure 5 This describes another illustrative configuration of the battery 400, which includes graded SEI 424. This configuration is similar in many respects to... Figure 1-3 and Figure 4 The configuration. Therefore, the descriptions of the configuration are combined here, and it is generally not necessary to repeat descriptions of topics that are common to the configuration.

[0056] refer to Figure 5 A graded SEI 424 is disposed between the separator 410 (i.e., electrolyte 412) and the negative electrode 406. In this illustrative example, the graded SEI 424 includes a first end 426, a second end 428 spaced apart from the first end 426, and a transition region 430 disposed between the first end 426 and the second end 428. The first end 426 may be coupled to and / or disposed on the negative electrode 306. According to one aspect, the first end 426 may be at least partially embedded in the negative electrode 406 (i.e., interlocked with the negative electrode 406). Figure 5 As shown, the negative electrode 406 is sandwiched between the graded SEI 424 and the first current collector 414 (e.g., a negative current collector). According to one aspect, the graded SEI 424 may have an SEI thickness T4 extending between a first end 426 and a second end 428. The transition region 430 may have a transition thickness T5 that is approximately half the SEI thickness T4.

[0057] The graded SEI 424 may include two or more materials with varying weight percentages between the first end 426 and the second end 428. In this illustrative example, the graded SEI 424 includes a first material 432 and a second material 434 different from the first material 432. Typically, the first material 432 may be a hard and / or inorganic-rich material that is stable relative to the material of the negative electrode 406 (e.g., lithium metal). The second material 434 may be a soft and / or organic-rich material that is stable relative to the material of the separator 410 (i.e., electrolyte 412). In this illustrative example, the transition region 430 includes at least some of the first material 432 and the second material 434. In other words, the weight percentage of the first material 432 and the weight percentage of the second material 434 are approximately equal to each other within the transition region 430. The weight percentage of the first material 432 gradually increases, while the weight percentage of the second material gradually decreases toward the first end 426. Similarly, the weight percentage of the second material 434 gradually increases, and the weight percentage of the first material 432 gradually decreases toward the second end 428. In other words, a first interface 436 can be defined between the graded SEI 424 and the negative electrode 406, such that the first interface 436 includes the material of the negative electrode and the first material 432. According to one aspect, the first material 432 may be a first major component of the graded SEI 424 at the first interface 436. Similarly, a second interface 438 can be defined between the graded SEI and the separator 410 (i.e., electrolyte 412), such that the second interface 438 includes the material of the electrolyte and the second material 434. According to one aspect, the second material 434 may be a second major component of the graded SEI 424 at the second interface 438.

[0058] For example, X-ray photoelectron spectroscopy (XPS) depth profiling can be used to examine the interactions between the first end 426 and the negative electrode 406, between the first material 432 and the second material 434 within the transition region 430, and / or between the second end 428 and the separator 410. Contrary to the previous configuration, the transition region 430 can be configured such that it does not include the defining boundary between the first material 432 and the second material 434.

[0059] Many embodiments have been described. However, it should be understood that various modifications can be made without departing from the spirit and scope of this disclosure. Therefore, other embodiments are within the scope of the appended claims.

[0060] The foregoing description is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or limiting of this disclosure. Elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where applicable and can be used in selected configurations, even if not specifically shown or described. They can also be varied in many ways. Such variations should not be considered as departing from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

Claims

1. A battery, comprising: Separation body; Conductive substrate; A negative electrode, which is connected to the conductive substrate; as well as A surface electrolyte interphase (SEI) disposed between the separator and the negative electrode, the surface electrolyte interphase comprising: The first layer is connected to the negative electrode and forms a first interface with the negative electrode. The second layer is connected to the first layer and forms a second interface with the separated body. The first layer is made of a first material, and the second layer is made of a second material different from the first material.

2. The battery according to claim 1, wherein the separator comprises an electrolyte.

3. The battery according to claim 1 further includes a third interface between the first layer and the second layer.

4. The battery of claim 3, wherein the first layer is made of a first film configured to adhere to a portion of the negative electrode, and the second layer is made of a second film configured to adhere to a portion of the first film.

5. The battery according to claim 3, wherein the third interface includes an interlocking portion of the first layer and the second layer.

6. The battery of claim 1, wherein the first layer has a first thickness and the second layer has a second thickness substantially the same as the first thickness.

7. The battery according to claim 1, wherein the first layer comprises an inorganic compound.

8. The battery according to claim 7, wherein the second layer comprises a compound rich in organic matter.

9. The battery of claim 1, wherein the first interface comprises a first material that is chemically stable relative to the negative electrode, and the second interface comprises a second material that is chemically stable relative to the separator.

10. The battery according to claim 1, wherein both the first layer and the second layer are formed by a process including in-situ electrochemical reactions.

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