WO2017037618A1

WO2017037618A1 - Substrate with doped diamond layer for lithium-based systems

Info

Publication number: WO2017037618A1
Application number: PCT/IB2016/055176
Authority: WO
Inventors: Leif Nyholm; David REHNLUND; Solveig BÖHME
Original assignee: Leif Nyholm; Rehnlund David; Böhme Solveig
Priority date: 2015-08-31
Filing date: 2016-08-30
Publication date: 2017-03-09

Abstract

An electrode has a diamond layer (500,520) with an inner-side oriented toward one or both of the first surface and the second surface of the substrate and an active layer having a composition that includes an element capable of lithium-atom insertion positioned on the outer-side of the layer(s) of diamond. The diamond layer includes polycrystalline diamond and a p-dopant element and has a doping level equal to or greater than 10²⁰ atoms/cm³ The doped diamond layer, preferably doped with boron, is essentially impermeable to lithium, which prevents lithium migration from the active layer during cycling of the electrode when utilized as one or more of an anode and cathode in a Li-ion battery. The boron-doped diamond electrode exhibited a stable capacity of about 250 μΑhcm^-2 and a coulombic efficiency of about 90 to 95% over 30 cycles. The electrode can be manufactured by CVD and electrochemical deposition techniques.

Description

SUBSTRATE WITH DOPED DIAMOND LAYER FOR

LITHIUM-BASED SYSTEMS

RELATED APPLICATION DATA

This application is based on and claims priority to U.S. Provisional Patent Application No. 62/211 ,898, filed August 31 , 2015, the entire contents of which are incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to substrates in environments containing highly reactive species. In particular, the present disclosure relates to substrates with a doped diamond surface that is exposed to an environment containing highly reactive species, such as lithium. The doped diamond exhibits conducting properties and the doped diamond surface improves chemical stability in the presence of the reactive species.

BACKGROUND

In the discussion that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention.

Since their commercialization, lithium-ion (Li-ion) batteries have contributed to the portable electronics revolution. Currently, Li-ion batteries are proposed and/or being developed for large-scale energy storage as well as for the transport industry with electric and hybrid electric vehicles. However, new electrode chemistries are required to meet the ever growing demand for increased energy density. Lithium-alloying (Li-alloying) materials are candidates for increased energy density applications because they can, theoretically, provide up to 10 times the energy density of currently used graphite. However there are presently obstacles limiting the lifetime and ultimately the use of Li-alloying materials in these applications. For example, Li-alloying materials suffer the disadvantage of large volume expansion during lithium insertion and removal leading to mechanical stress and irreversible Li losses by reactions with the electrolyte. Li losses can also occur when metallic lithium is inserted in materials (e.g. metals) that have some solubility for lithium or an alloy phase with lithium. This phenomena has been seen for Li-alloys commonly used as electrode materials (i.e. silicon and aluminium), however, it is expected to also be an issue if metallic Li is trapped in the current collector (e.g. copper or nickel).

The drawbacks of conventional current collector materials are demonstrated by the experimental results shown in FIG. 1 , which is a series of graphs of voltage as a function of time (FIGS. 1 a and 1d), capacity and coulombic efficiency as a function of cycle (FIGS. 1 b and 1e) and capacity as a function of cycles^"172 (FIGS. 1c and 1f) for a copper current collector (FIGS. 1 a, b, c) and a titanium current collector (FIGS. 1d, e, f). The electrodes were prepared by first growing Cu nanorods on Cu and Ti substrates and subsequently electrochemically coating the electrodes with Li metal. Both samples were then placed in a Li-ion battery and cycled versus a counter electrode of Cu₂0 coated Cu nanorods grown on Cu substrate. The cell was cycled for 100 cycles while recording the individual electrode potentials as well as the cell capacity. Rapid capacity decline was observed in both cases (see FIGS. 1 b and 1e) and was connected to irreversible lithium losses into the substrate (i.e. Cu and Ti). The results illustrate the loss of lithium into the current collector during cycling of a Li-ion battery utilizing the respective current collectors.

Lithium trapping in these materials has been experimentally corroborated using Inductively Coupled Plasma with an Atomic Emission Spectrometer (ICP-AES).

Copper, Titanium and Nickel, all common current collectors in Li-ion batteries, were placed in contact with lithium metal and sealed under inert atmosphere (i.e., Argon gas with <1 ppm 0₂ and H₂0) and left to react for 1 week at 60 °C. The lithium metal was then removed and the samples were analyzed using ICP-AES. The results are shown in Table 1. Table 1

Table 1 shows a considerable amount of residual lithium in all samples. The amounts are comparable in the different current collectors indicating that these commonly used current collector metals are not suitable for Li-ion batteries where they come in contact with metallic Li.

To shield the current collector, it has been proposed to use a barrier layer composed of TiN or TaN to protect the current collector from Li insertion. However, barrier layers composed of TiN or TaN have also been shown to exhibit Li diffusion through the material. Lithium metal encapsulated by BN thin films have also been proposed, but evaluation of the film showed that it was covered with small defects (i.e. holes) that enabled Li transport through the film.

SUMMARY

Doped diamond material, particularly boron doped diamond material (hereinafter referred to as B-diamond), is inert and impermeable to lithium. In these structures, diamond exhibits a close packed structure with high chemical stability, for example, chemically stable to highly corrosive acids including HN0₃ and HF, making it capable of withstanding chemical reactions with highly reactive species, for example, lithium. Doping the diamond to levels sufficient to transform the diamond from an insulator to a metallic-like conductor, for example for boron doping, to doping levels equal to or greater than 10²⁰ atoms/cm³ and less than 10²³ atoms/cm³ preferably equal to or greater than 10²¹ atoms/cm³ and less than 10²² atoms/cm³, forms a doped diamond and this material is suitable for applications where electronic conduction is required.

Doped diamond can be used as a stand-alone substrate or coating on a wide variety of different substrates depending on their use in the final application. For example, doped diamond can be deposited as a coating on a substrate material. If deposited as a thin film on a flexible substrate (e.g. carbon), a flexible product could be further fabricated. One example of a doped diamond electrode deposits a 4.5 μηι thick layer of B-diamond on a Si wafer substrate.

One or more doped diamond electrodes, particularly B-diamond electrodes, can be incorporated as electrode(s) (as one or more of an anode and a cathode) in Li-ion batteries where lithium comes into contact with a material that forms an alloy or has some solubility with lithium. The protection provided by the doped diamond electrode(s) works in two parts. First, the doped diamond electrode allows the use of Li as an anode material (in its metallic state or in a Li-alloy, e.g. Li_{3 75}Si) without Li leakage into the substrate, which increases the battery cell lifetime. Second, the doped diamond electrode can be effectively used as current collector for anode materials where Li insertion occurs close to the Li⁺/Li standard potential and protects the current collector from possible Li plating during low voltage operation (i.e. as is the case with the commonly used electrode material graphite).

An embodiment of an exemplar electrode comprises a substrate including a body having a first surface opposing a second surface, a layer of diamond including an inner-side oriented toward at least one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side, and an active layer on the outer-side of the layer of diamond, wherein the layer of diamond includes polycrystalline diamond and a p-dopant element, wherein the layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³ and less than 10²³ atoms/cm³, preferably equal to or greater than 10²¹ atoms/cm³ and less than 10²² atoms/cm³, and wherein the active layer has a composition that includes an element capable of lithium-atom insertion.

An embodiment of an exemplar battery comprises a plurality of anodes electrically connected to a negative terminal, a plurality of cathodes electrically connected to a positive terminal, and a Li-ion electrolyte solution between the plurality of anodes and the plurality of cathodes, wherein a first group of the plurality of anodes and a first group of the plurality of cathodes have electrodes including a first substrate having a body with a first surface opposing a second surface, a first layer of diamond having an inner-side oriented toward the first surface of the substrate and an outer- side opposing the inner-side, a second layer of diamond having an inner-side oriented toward the second surface of the substrate and an outer-side opposing the inner-side; a first active layer on the outer-side of the first layer of diamond, and a second active layer on the outer-side of the second layer of diamond, wherein a second group of the plurality of anodes and a second group of the plurality of cathodes have electrodes including a second substrate having a body with a third surface opposing a fourth surface, a third layer of diamond having an inner-side oriented toward the third surface of the substrate, and a third active layer on the outer-side of the third layer of diamond, wherein each of the first layer of diamond, the second layer of diamond, and the third layer of diamond includes polycrystalline diamond and a p-dopant element, wherein each of the first layer of diamond, the second layer of diamond and the third layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³, wherein each of the first active layer, the second active layer, and the third active layer has a composition that includes an element capable of lithium-atom insertion, wherein outside of one end of the first group of the plurality of anodes is a cathode from the second group of the plurality of cathodes and one of the first and second active layer of the anode from the first group is oriented toward the third active layer of the cathode from the second group, and wherein outside of one end of the first group of the plurality of cathodes is a anode from the second group of the plurality of anodes and one of the first and second active layer of the cathode from the first group is oriented toward the third active layer of the anode from the second group.

An embodiment of an exemplar method of manufacturing an electrode comprises depositing a first layer of diamond on a substrate, wherein the substrate includes a body having a first surface opposing a second surface and the deposited first layer of diamond includes an inner-side oriented toward a first one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side, and forming a first active layer on the outer-side of the deposited first layer of diamond, wherein the first layer of diamond includes polycrystalline diamond and a p-dopant element, wherein the first layer of diamond is doped with the p- dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³, and wherein the first active layer has a composition that includes an element capable of lithium-atom insertion. The exemplar method of manufacturing can further comprise depositing a second layer of diamond on the substrate, wherein the deposited second layer of diamond includes an inner-side oriented toward a second one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side, and forming a second active layer on the outer-side of the deposited second layer of diamond, wherein the second layer of diamond includes

polycrystalline diamond and a p-dopant element, wherein the second layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³, and wherein the second active layer has a composition that includes an element capable of lithium-atom insertion.

While the electrodes and related structures and methods disclosed herein will be particularly described with respect to a lithium-based system and also with respect to B-diamond, many varieties of doped diamond electrodes and related structures and methods disclosed herein are generally applicable to many types of electrochemical systems and may be used in any appropriate electrochemical system, such as a battery, a supercapacitor or a fuel cell.

BRIEF DESCRIPTION OF THE DRAWING

The following detailed description of preferred embodiments can be read in connection with the accompanying drawings in which like numerals designate like elements and in which:

FIGS. 1 a to 1f are graphs showing results of cyclic voltammetry studies of Li-ion microbattery whole cells with Cu₂0/Cu nanorods (WE) cycled vs. Li/Cu nanorods (CE). Working electrode (WE) and counter electrode (CE) potential detection was used via a three electrode setup with Li as reference electrode (RE). The counter electrodes were electrodeposited on Cu (for FIGS. 1a-c) and Ti (for FIGS 1d-f). FIG. 2 is a schematic, cross-sectional view of an exemplar electrode showing the substrate, the doped diamond layer and the active layer.

FIG. 3 is a schematic, cross-sectional view of another exemplar electrode showing the substrate, a doped diamond layer on each side of the substrate, and an active layer on each of the doped diamond layers.

FIGS. 4a to 4c are schematic, partial cross-sectional views of exemplar electrodes showing different variations for the structure and features of the active layer.

FIG. 5 is a schematic representation of a B-doped diamond electrode in a Li-ion battery cell (FIG. 5a) including a partial, cut-away cross-sectional view of the electrode (FIG. 5b). The electrode is comprised of an active layer on B-doped diamond on top of a substrate of a suitable material, e.g., silicon.

FIG. 6 is a schematic, cross-sectional view of one arrangement of electrodes showing embodiments of the electrodes variously as anodes and cathodes in a battery. FIGS. 7a to 7c are a Scanning Electron Spectroscopy image of B-diamond deposited on top of a silicon wafer (FIG. 7a) and energy-dispersive spectroscopy of the interfacial region showing the distribution of carbon (FIG. 7b) and silicon (FIG. 7c) and that the film is made up of a layer of mostly carbon (corresponding to diamond) on top of a silicon substrate.

FIG. 8 shows the results of Raman spectroscopy analysis of B-diamond sample presenting characteristic sp3 and sp2 hybridized diamond peaks with a shift due to the boron-doping. FIG. 9 is a Mott-Schottky plot obtained by impedance spectroscopy of a B-diamond sample, from which a boron doping level of 2.93 x 10²¹ atoms/cm³ was determined. FIG. 10 contains results from Li diffusion experiments and detail the Li content (in μς) in B-diamond in contact with Li foil as measured by ICP-AES (FIG. 10a) and a comparison of Li content in Ni, Cu, Ti and B-diamond (FIG. 10b). FIG. 11 is a graph showing capacity (left axis, in μΑϊιαη^"2) and coulombic efficiency (right axis, in %) as a function of cycle number (x-axis) for electrochemical analysis of B-diamond as a current collector in a Li-ion battery. Li metal was reversibly plated and stripped from the diamond surface while monitoring the capacity of each process and the corresponding efficiency of this process. A comparative reference cell with copper as current collector was also studied.

FIG. 12 is the C1 s spectra detailing B-diamond cycled in a Li-ion battery analyzed using Hard X-ray Photoelectron Spectroscopy (HAXPES) at 6015 eV incoming X-ray energy.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, the use of similar or the same symbols in different drawings typically indicates similar or identical items, unless context dictates otherwise.

The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here.

One skilled in the art will recognize that the herein described components (e.g., operations), devices, objects, and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration

modifications are contemplated. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be

representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be taken as limiting.

The present application uses formal outline headings for clarity of presentation. However, it is to be understood that the outline headings are for presentation purposes, and that different types of subject matter may be discussed throughout the application (e.g., device(s)/structure(s) may be described under

process(es)/operations heading(s) and/or process(es)/operations may be discussed under structure(s)/process(es) headings; and/or descriptions of single topics may span two or more topic headings). Hence, the use of the formal outline headings is not intended to be in any way limiting.

Diamond has advantageous properties such as high mechanical hardness (Vickers hardness of 90 GPa to 100 GPa, alternatively about 98 GPa), high room temperature thermal conductivity (greater than 1.8 x 10³ Wm^"1K^"1, alternatively between 1.8 x 10³ Wm^"1 K^"1 and 2.2 x 10³ Wm^"1 K^"1, at 300K (26.85 °C)) and very high chemical stability (meaning, in this context, that the material is essentially inert to solvents at room temperature and subject to oxidative erosion by atomic oxygen at a rate of no greater than 0.12 nm/min) as well as electronic insulation arising from the short and extremely strong carbon-carbon (sp3) bonds within its structure. The very dense and stable structure of diamond negates diffusion of almost all elements (hydrogen being the sole exception), including Li. Diamond is inherently electronically insulating but can be modified to offer metallic-like electronic conduction by doping the material (e.g. n-type or p-type). P-type doping can be achieved with B and Al dopants; n-type doping can be achieved with N, P and S dopants. The most common p-type doping to yield metallic-like conduction (i.e., range of 10

Siemens/centimeter (S/cm) to 20000 S/cm) even at room temperature is with boron. N-type doping is typically produced by nitrogen doping, however the n-doped diamond is not conductive at room temperature, but rather needs higher temperature due to the size of the band gap for N-doped materials, which is 1.7 eV for nitrogen doped diamond materials. Because of these properties, doped-diamond coatings, layers or films on a substrate as well as standalone substrates can, by their electronic conduction and chemical properties, be used as barrier layers for highly reactive species, such as lithium, for current collectors for applications that require a conductive substrate with control of the reactive species content (e.g., in Li-ion batteries). FIG. 2 is a schematic, partial cross-sectional view of an exemplar electrode 100 including a substrate 102, a doped diamond layer 104 and an active layer 106. The substrate includes a body 108 having a first surface 1 10 opposing a second surface 112 (not shown in FIG. 2). The layer of diamond 104 includes an inner-side 116 oriented toward at least one of the first surface 1 10 of the substrate 102 and the second surface 112 of the substrate 102. In the exemplary embodiment in FIG. 2, the inner-side 116 of the layer of diamond 104 is oriented toward the first surface 110 of the substrate 102. Alternatively or additionally, the inner-side 1 16 of the layer of diamond 104 is in direct contact with the first surface 110 of the substrate 102. Optionally, an intervening bonding layer or layer to compensate for differences in thermal expansion may be placed between the inner-side 116 of the layer of diamond 104 and the first surface 1 10 of the substrate 102. An outer-side 118 of the layer of diamond 104 opposes the inner-side 116. The active layer 106 is on the outer-side 1 18 of the layer of diamond 104. Alternatively or additionally, the outer- side 118 of the layer of diamond 104 is in direct contact with the second surface 112 of the substrate 102. Optionally, an intervening bonding layer or layer to

compensate for differences in thermal expansion may be placed between the outer- side 118 of the layer of diamond 104 and the second surface 1 12 of the substrate 102. In additional or alternative embodiments, the electrode can have a doped diamond layer and an active layer on a second side of the substrate as well as on the first side of the substrate. FIG. 3 is a schematic, cross-sectional view of another exemplar electrode 100 showing the substrate 102, a doped diamond layer 104,104' on each side of the substrate 102, and an active layer 106, 106' on each of the doped diamond layers 104, 104'.

The substrate 102 can be any suitable substrate on which the diamond layer can be deposited and which provides mechanical support to the electrode and can be either a rigid body or a flexible body. For example, the substrate 102 can be a metal, such as titanium, tungsten, and niobium, or a semiconductor, preferably an elemental semiconductor such as Si or an lll-V semiconductor such as GaAs. As another example and if a flexible substrate is desired, the substrate 102 can be carbon or molybdenum. The composition of the substrate can be selected to provide a chemical bond between the substrate and the subsequently deposited doped diamond layer 104, 104'. Further, materials of the substrate may be selected so that the differences in thermal expansion between the material of the substrate 102 and the layer of diamond 104, 104' at typical process temperatures, e.g., about 700 °C for chemical vapor deposition (CVD)-based processes, are sufficiently matched to minimize or reduce intrinsic residual stress induced in the materials during manufacturing.

The body of the substrate can be any suitable shape. For applications related to high surface area applications, the shape of the body can be planar, with the first surface 110 and opposing a second surface 112 connected by edge surfaces 114 and separated by a thickness. Typically, the dimensions of the planar surface (width and length) of the substrate 102 are an order of magnitude or greater than the dimension of the thickness of the substrate 102. Additionally or alternatively, the first surface 110 and the second surface 112 can be textured or roughened to increase the mechanical connection between the substrate 102 and the subsequently deposited doped diamond layer 104, 104'.

The layer of diamond 104,104' has a composition that includes diamond and a dopant. Although predominantly described and discussed herein as boron-doped diamond, the diamond can be doped by any suitable dopant. For example, the dopant may be either a p-dopant or a n-dopant. Examples of p-dopants include boron and aluminum; examples of n-dopants include nitrogen, phosphorus and sulfur. The dopant is present in an amount sufficient to transform the layer of diamond from an insulator to a metallic-like conductor, e.g., having a conductivity about 10 Siemens/centimeter or greater. An example of a sufficient doping level for boron as a dopant is above 10²⁰ atoms/cm³ and less than 10²² atoms/cm³. In some exemplar embodiments, the diamond in the layer of diamond is polycrystalline diamond and the dopant element is boron. In alternative or additional embodiments, the region of the diamond layer is doped with the p-dopant or n-dopant only in a region of the diamond layer and an interior region is un-doped. This doped region is located from an exposed surface inward to a sufficient depth to provide electrical conductivity between edges of the doped area. In some embodiments, the doped region extends across the entire thickness of the substrate from the inner-side 116 to the outer-side 1 18. This doped area with electrical conductivity (with or without the substrate 108) can function as the current collector in an electrochemical cell. The diamond layer may have a layer thickness of between 0.2 μηι and 20 μηι, alternatively between 1 μηι, 2 μηι or 4 μηι and 5 μηι, 6 μηι or 10 μηι. The lower thickness limit is determined by successful nucleation with seed diamond

nanocrystals while providing full coverage of the substrate and a depth sufficient for doping by the dopant to achieve a requisite minimum electrical conductivity. While there are no theoretical upper limits on the thickness of the diamond layer, there are prudential and practical limits on the upper limit of thickness based on, for example, mechanical properties, deposition equipment parameters and the intended application for which the diamond layer or diamond coated substrate is being used. Preferably, the diamond layer has a thickness of about 4.5 μηι. The diamond layer can be polycrystalline. In alternative embodiments, the diamond layer can have a single crystal character.

The active layer 106,106' has a composition that includes an element capable of lithium atom insertion. For example, the active layer can have a composition that includes Si, Sn, Al, Li or Ge. The active layer is on the outer-side of the layer of diamond, typically directly in contact with the layer of diamond, and is formed by deposition processes such as sol-gel, electrodeposition, Physical Vapour Deposition (PVD), Chemical Vapour Deposition (CVD) and sputtering processes, as suitable for the chemistry of the composition of the active layer.

The active layer 106, 106' can have a planar outer surface, a textured or roughened outer surface, or a combination of such surfaces. FIGS. 4a to 4c are schematic, partial cross-sectional views of exemplar electrodes showing different variations for the structure and features of the active layer. In FIG. 4a, an exemplar electrode 200 is depicted with an active layer 202 on the outer side 204 of the doped diamond layer 206. The active layer 202 extends in a plane (in the depicted embodiment, extending in the x-y plane) and has a substantially planar outer surface 208.

In FIG. 4b, an additional or alternative exemplar electrode 220 is depicted with an active layer 222 on the outer side 224 of the doped diamond layer 226. The active layer 222 extends in a plane (in the depicted embodiment, extending in the x-y plane) and includes a plurality of oriented bodies 228 extending outwardly from the outer side 224 of the doped diamond layer 226. The oriented bodies 228 have a height (h) and a width (w) and are separated by a separation distance (d).

In FIG. 4c, an additionally or alternative exemplar electrode 240 is depicted with an active layer 242 on the outer side 244 of the doped diamond layer 246. The active layer 242 has both a first region 248 and a second region 250. In the first region 248, the active layer 242 extends in a plane (in the depicted embodiment, extending in the x-y plane) and has a thickness (hi). In the second region 250, the active layer 242 also extends in a plane (in the depicted embodiment, extending in the x-y plane) but the active layer 242 also includes a plurality of oriented bodies 252 extending outwardly from the first region 248. The oriented bodies 252 have a height (h2) and a width (w1) and are separated by a separation distance (d1). Between sequentially adjacent oriented bodies 252 of the second region 250, the first region 248 has a substantially planar outer surface 254. The first region 248 and the second region 250 are preferably a unitary body, but can also be constructed as two separate bodies contacting each other at an interface.

Additionally or alternative, in either one or both of the exemplar embodiment in FIG. 4b and the exemplar embodiment in FIG. 4c, the separation distance (d, d1) can be at least as large as the size (i.e., diameter or dimension of greatest extent) of the atom(s) of the reactive species, such as a Li-atom, to be inserted into the active layer 222, 242, alternatively at least a multiple of three of the size of such atom(s), to allow for efficient atom movement into and out of the active layer 222, 242 during multiple insertion cycles. Also additionally and alternatively, the oriented bodies 228, 252 can be of any suitable geometric form and structure. For example, the oriented bodies 228, 252 can be lines (for example, extending in the X-Y plane in FIGS. 4b and 4c) or can be columnar or can be a mesa with an irregular top planar surface area or a combination of such geometric forms and structures. The oriented bodies can be formed by photolithographic techniques or preferential deposition or etching processes or template-assisted deposition techniques or a combination of these techniques, depositions and processes.

Additionally or alternative, any of the electrodes disclosed herein can be lithiated, in whole or in part. To lithiate the electrode, the electrode is exposed to metallic lithium either depositing lithium on the electrode (e.g. via electrodeposition or melting) or placing lithium in contact with the electrode (preferably at elevated temperatures to increase diffusion rates). The amount of inserted Li in the crystal structure of the active layer varies depending on the host. In exemplary embodiments, lithiated electrodes can contain in the crystal structure of the active layer between 0 and 4.5 Li formula units per host atom. The maximum value for a lithiated electrode is for Li_{4 5}Pb. The mechanism of insertion is typically reduction of Li-ions to Li-atoms which can either be hosted in an active material (i.e. alloying materials such as Si and Al) or deposited on the surface of the electrode to later diffuse into its crystal structure.

FIG. 5 is a schematic representation of a doped diamond electrode, e.g., B-diamond electrode, in a Li-ion battery cell (FIG. 5a) including a partial, cut-away cross- sectional side view of one of the electrodes (FIG. 5b). The electrodes are comprised of doped diamond on top of a substrate of a suitable material, e.g., silicon. The Li- ion battery cell 300 includes two electrodes 302, 304 (electrode 304 not visible in FIG. 5), at least one of which, alternatively both of which, include a substrate 306, a layer of doped diamond 308, and an active layer 310 on the outer-side of the layer of doped diamond 308. The electrodes are independently electrically connected to a respective contact 312, 314, such as an electrically conductive metal wire or metal strip. The electrical connection can be to the layer of doped diamond 308 or to the substrate 306, if the substrate is sufficiently electrically conductive such as a metal, or a combination thereof. When Si is used for the substrate, it is preferred to make the electrical connection to the doped diamond 308. A separator 316 suitable for the chemistry of the electrochemical system of the Li-ion battery cell 300 is positioned between the two electrodes 302, 304, one of which functions as an anode and the other of which functions as a cathode in the Li-ion battery cell 300. An example of a suitable separator for a cell 300 with a B-diamond electrode, a lithium metal active layer and a 1 M LiPF₆ in EC: DEC 1 : 1 (ethyl carbonate and diethyl carbonate, 1 : 1 ratio) electrolyte is a polyethylene membrane (such as the Ultra High Molecular Weight Polyethylene sold under the trade name Solupor® by Lydall Performance Materials, a division of Lydall, Inc.). The electrodes 302, 304, separator 316 and an electrolyte (not shown) suitable for the battery chemistry are contained within an outer housing 318, such as a sealable pouch or a rigid container.

FIG. 6 is a schematic representation of a multiple electrode battery incorporating doped diamond electrodes disclosed herein as either anodes, cathodes or both anodes and cathodes. The battery 400 in FIG. 6 includes anodes 402a, 402b, 402c and cathodes 404a, 404b, 404c. Any of the doped diamond electrodes as disclosed and described herein can be used as the anodes and/or cathodes of the battery 400. In battery 400, an active layer 406 of an anode faces and is separated from an active layer 408 of a cathode by one or more of an electrolyte and a separator (not shown), which is present in regions 410 between opposing anodes and cathodes. Two types of electrodes are incorporated into the battery 400. A first type of electrode has an active layer and a doped diamond layer on only one side of the substrate; a second type of electrode has an active layer and a doped diamond layer on both sides of the substrate. The first type of electrode, whether a cathode or an anode, is used as the suitable type of end electrode (i.e., either an anode or a cathode) at respective first end 412 and second end 414 of the arrangement of electrodes in the battery 400. The second type of electrode, whether a cathode or anode, is used as an interior electrode between the first type of electrode at the respective first end and second end. In FIG. 6, anode 402a and cathode 404a are each representative of the first type of electrode; anodes 402b, 402c and cathodes 404b, 404c are each

representative of the second type of electrode. The anodes 402a, 402b, 402c and cathodes 404a, 404b, 404c are electrically connected to a positive terminal 416 and a negative terminal 418, respectively. Further, the anodes 402a, 402b, 402c and cathodes 404a, 404b, 404c are arranged within an outer casing 420, which can take suitable forms as known in the art, such as a chemically inert pouch, the outer casing of a prismatic or cylindrical battery, and so forth. In FIG. 6, the electrical connections to the anodes and cathodes are to the substrate 430, but in alternative or additional embodiments, the electrical connections can be made to the B-diamond layers 432.

The electrodes in the battery can incorporate one or more lithiated electrodes. For example, exemplar embodiments of the battery can include a lithiated cathode and a non-lithiated anode. Alternatively, exemplar embodiments of the battery can include a lithiated anode and a non-lithiated cathode. Further alternatively, exemplar embodiments of the battery can include a partially-lithiated cathode and a partially- lithiated anode. As a further alternative, the degree of lithiation of the respective partially-lithiated cathode and partially-lithiated anode can be balanced. For any two electrodes arranged as anode and cathode, the electrodes as a whole contain lithium to some degree (i.e. 0-100%) and the battery cell state of charge (i.e. 0-

100%) is then determined by the balance between the lithiation of the anode and the lithiation of the cathode, respectively.

Diamond (doped or undoped) can be fabricated by High-Pressure High-Temperature (HPHT) techniques or Chemical Vapor Deposition (CVD) techniques. CVD deposition techniques can produce diamond films on a wide variety of substrates. Hot-filament and microwave assisted CVD techniques are among those suitable for preparing diamond films. Characteristics of exemplar substrates include a higher melting point (typically above 700 °C), a thermal expansion similar to diamond to prevent delamination of the film, and the ability to form a carbide so as to provide a good nucleation layer and provide adhesion to the diamond film. Some

representative elements exhibiting one or more of these properties include Si, Mo, Ti, Zr, Hf, V, Nb, Ta, Cr, W, Co, Ni, Y, Al, and certain rare-earth metals, such as La, Ce, Pr, Nd and Y. Preferably, the substrates are Si or Mo, which have a very thin outer carbide phase with a thickness of 1 nm to 10 nm, alternatively 1 nm to 5 nm). Si and Mo can also act as a seed layer for CVD diamond growth on otherwise unsuitable substrates by first depositing a thin film of Si or Mo on the substrate. CVD deposition techniques are also capable of producing standalone diamond substrates by first growing the film on a substrate and later removing the film (chemically or mechanically). CVD offers the benefit of being able to coat substrates with a diamond film (doped or undoped) at rates ranging from 1 to several hundreds of μΓΤΐ/hour, depending on the specific growth mechanism used. Doped diamond films can also be fabricated with excellent control of doping levels. The precursors used in CVD are typically methane gas and hydrogen gas mixed with possible doping elements in the gas phase (e.g. B₂H₆ or B(CH₃)₃ for boron doping).

Boron-doped diamond electrodes were prepared by hot filament chemical vapour deposition (HFCVD). Si substrates were seeded with nanodiamond crystallites (i.e., 4-5 nm large) in water during ultrasonic treatment after which the substrates were cleaned with ethanol. B-diamond growth was then performed in the HFCVD chamber at 700 °C and a constant pressure of 5 Torr by introducing 99 standard cubic centimeter (sscm) hydrogen, 1 sscm methane and 0.01 sscm gaseous trimethyl borane (B(CH₃)₃). The substrates were continuously rotated during the 4 h deposition. The B-diamond substrates were subsequently coated with lithium by electrodeposition. The procedure was carried out in a polymer covered aluminum pouch cell where the B-diamond substrate was placed versus Li foil and separated by a porous polymer membrane (Solupor®) soaked in 1 M LiPF₆ dissolved in a mixture of ethylcarbonate and diethylcarbonate (1 :1 ratio). Li plating was performed at a constant current density of 100 μΑ/cm² and ultimately deposited 3.6 C lithium.

EXAMPLES: An electrode with a B-diamond layer was prepared and tested. Boron- doped diamond was fabricated by HFCVD on silicon wafers from gases including hydrogen, methane and trimethyl borane (B(CH₃)₃) as described above.

Characteristics of the diamond film were analyzed by Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) and the results are shown in FIG. 7. The diamond film 500 has a thickness of 4.0 ± 0.1 μηι and is polycrystalline in nature with the diamond crystals in a general columnar shape (FIG. 7a) extending outwardly from the surface of the silicon substrate 510. EDS on the same sample (FIGS. 7b and 7c) show a mapping of the distribution and relative proportion

(intensity) of carbon (in area 520 FIG. 7b) and silicon (in area 530 in FIG. 7c). The imagery in FIGS. 7b and 7c confirm that the diamond film 500 was mainly composed of carbon lying on top of silicon and that the diamond and silicon have a well-defined interface. The diamond layer 500 is composed of primarily diamond and the silicon substrate 510 is composed of primarily silicon. The B-diamond is polycrystalline. Results from electrochemical analyses on the sample showed no limitation from resistance in the B-diamond layer indicating the distribution of the dopant boron in the diamond layer is sufficiently homogenous to allow metallic conduction.

FIGS. 8 and 9 show further experimental results on a sample of boron-doped diamond material deposited on a silicon wafer. FIG. 8 is Raman spectroscopy analysis of a B-diamond sample showing intensity (in arbitrary units) as a function of wavenumber (1/cm). The results indicate a characteristic sp3 hybridized diamond peak at 1329 cm^"1 as well as two broad bands around 500 and 1220 cm^"1 connected to the two maxima of phonon density of states for boron doped diamond. A slight shift was observed, primarily for the sp3 hybridization, to lower wavenumber by 4 cm^" ¹ as is expected for B-doped diamond due to the Fano-type interference between the discrete zone-center and continuum of electronic states induced by boron doping. The final peak at 1536 cm^"1 is indicative of the existence of sp2 hybridized carbon atoms on the surface. FIG. 9 is a Mott-Schottky plot obtained by impedance spectroscopy of a B-diamond sample. The Mott-Schottky plot was used to characterize the doping level of the diamond layer. The Mott-Schottky plot is linear over the potential range of about 0.4 V to about 1.0 V. The slope of the linear part of the curve can be used to determine the acceptor concentration (i.e., the boron concentration in this instance) by using the equation Nd = 21 qss₀ (slope)^~l , where q is the electronic charge, ε is the dielectric constant for diamond, and ε₀ is the relative permittivity of free space. A linear curve fit over this potential range had a curve fit of y = -8.75 x l0⁹ + 1.72 x lO¹⁰ indicating the B-diamond sample was p-doped. Using the Mott-Schottky results, the acceptor concentration, N_d, was calculated to be 2.93 ^χ 10²¹ atoms/cm³ (based on the slope of -8.75 x 10⁹). A flat band potential (E_fb) was also determined as E_fb = 1.966 V

(based on the intersection of the linear line with the potential axis). Based on its doping level, the conductivity of this sample was approximately 1000 Siemens/centimeter, which was found to be sufficient for the intended application as an electrode in a battery system.

The experimental analysis reported in FIGS. 8 and 9 are from the same sample; the experimental analysis reported in FIG. 7 is from a different, but nominally the same, sample as the sample from FIGS. 8 and 9.

To investigate if lithium diffuses into doped diamond material, an experiment was performed on doped diamond materials that was analogous to the experiment performed on Cu, Ti and Ni and reported in Table 1. In the experiment on doped diamond material, Li metal was placed in contact with B-diamond and sealed under inert atmosphere (i.e. argon gas with <1 ppm 0₂ and H₂0) and left to react for up to

1 week at 60 °C. The lithium metal was then removed from contact with the B- diamond and the surface of the B-diamond was quickly cleaned with a small amount of water to remove any residual lithium on the surface, as this would give a false indication of the amount of lithium remaining inside the sample. The cleaned samples were dissolved in an acid treatment by three times digesting them in sub- boiled nitric acid (HN0₃) and concentrated hydrofluoric acid (HF) at 100 °C over 12 hours. After digestion, the samples were quantitatively transferred to a storage and centrifuging tube (i.e., a Falcon™ tube) and diluted to 50 ml with MQ-filtered ultrapure water. This procedure extracts any lithium content in the B-diamond samples for quantitative analyses. The lithium content in the B-diamond samples for different exposure times was then analyzed by ICP-AES. The results of the lithium content analysis on the above sample are presented in FIG. 10. A lithium content of about 0.1-0.25 μg was detected in the B-diamond samples regardless of the amount of exposure time to lithium during the experiment (FIG. 10a). The graph in FIG. 10a indicates that the lithium content ^g Li) remained stable over time, particularly after the 1 to 2 days of exposure, and demonstrates that there is no lithium diffusion into the B-diamond material. Each data point presented in FIG. 10a represents an average of three measurements. The lithium content in the B-diamond samples was also compared to the previously analyzed Cu, Ti and Ni samples (see Table 1) and this comparison is shown graphically in FIG. 10b (Li content reported in μg). B-diamond has residual lithium content of 0.11 μg as compared to 8.9, 10.6 and 14.9 μg for Ni, Cu and Ti, respectively. In alternative terms, B-diamond facilitates about one hundredth of lithium as compared to the metals. Accordingly, it is concluded that B-diamond essentially does not trap lithium and is superior to metals in this regard.

B-diamond was also investigated electrochemically as a current collector in a Li-ion battery. The setup included placing a B-diamond electrode versus lithium separated by a plastic membrane formed from porous polyethylene (examples of suitable membrane materials include Ultra High Molecular Weight Polyethylene sold under the trade name Solupor® by Lydall Performance Materials, a division of Lydall, Inc.). The plastic membrane had a thickness of 15 μηι and an area of approximately 2 cm² and was soaked in 50 liters of 1 M LiPF₆ dissolved in Ethyl Carbonate: Diethyl

Carbonate (EC: DEC) with a 1 : 1 volume ratio. The electrode in the assembled cell had no pre-deposited active layer, but rather the active layer, i.e., the lithium, was plated in situ to the assembled cell and then reversibly cycled. Lithium was reversibly plated and stripped from the surface with a fixed amount of lithium plated each cycle. The cell capacity and corresponding coulombic efficiency was recorded for the diamond cell as well as a reference cell with copper as a current collector. The results are presented in FIG. 11. Calculating from the reversible charge obtained during cycling, the Li film had an approximate thickness of 300 ± 40 nm. Stripping lithium on B-diamond (600, solid large circles) yielded a higher capacity than lithium stripping on copper (602, open large circles). B-diamond stripping remained stable at about 250 μΑΙιοηΥ² over 30 cycles, while after about cycle 12 of the experiment, the copper stripping capacity started to decrease from about 230 μΑΙιατΓ² to about 200 μΑϊιοηι ² and continued to decrease over subsequent cycles throughout the experiment.

FIG. 11 also shows coulombic efficiency, which compares plating and stripping charge and thereby gives an indication of the reversibility of the process. Here, the coulombic efficiency of a B-diamond electrode (610, open small circles) is, at each cycle, higher than the coulombic efficiency of a copper electrode (612, solid small circles). The B-diamond electrode outperformed the copper electrode with a coulombic efficiency of about 90 to 95% over 30 cycles (after an initial conditioning process over cycles 1-4).

Ideally, the B-diamond electrode system should deliver close to 100% efficiency. However, inhomogeneous lithium plating on the surface of the B-diamond electrode can yield irreversible reactions with the electrolyte that affects the capacity. Poor adhesion between the deposited lithium and the active layer of the B-diamond surface can also be present, which could result in Li breaking of the surface and ultimately lowering the stripping capacity. However, these potential phenomenon are not limiting for the performance of doped diamond as current collector since it does not reflect on the doped diamond's prime responsibility of supplying current to the system while keeping the amount of lithium constant in the cell.

Post-mortem analyses were performed on a B-diamond electrode exposed to reversible Li plating and stripping in a Li-ion battery (as previously detailed) using Hard X-ray Photoelectron Spectroscopy (HAXPES) at 6015 eV incoming X-ray energy. A cycled battery cell was dismantled and the B-diamond electrode removed in a glovebox (with controlled [0₂] and [H₂0] levels < 1 ppm) and washed in dimethyl carbonate so as to remove excess electrolyte. The B-diamond electrode was then transported and analyzed by HAXPES using synchrotron sourced X-rays with an incoming energy of 6015 eV. These highly energetic X-rays enabled penetration into the bulk B-diamond (i.e. at a distance where surface species where no longer visible). As such it was possible to investigate if lithium species had penetrated into the diamond bulk during cycling (i.e. by diffusion) by monitoring the characteristic diamond sp3 hybridized C-C bond.

FIG. 12 is the C1 s spectra detailing B-diamond cycled in a Li-ion battery analyzed using HAXPES. In FIG. 12, the results from the B-diamond cycled in a Li-ion battery (700) are shown as well as the results from a clean, uncycled B-diamond electrode (710), which can be used as a reference. The intensities in FIG. 12 are displayed as measured and calibrated to the Au4f reference peak. The sp3 C-C peak at 284.5 eV is very well aligned between the sample (700) and the reference (i.e. a clean B- diamond substrate (710)). The lack of a clear peak shift for the cycled B-diamond indicates that no significant amount of lithium is present in the bulk as lithium inclusions would be expected to shift the C-C peak binding energy. Accordingly, post-mortem HAXPES analysis shows that the B-diamond electrode is resistant to lithium penetration during cycling.

Although the present invention has been described in connection with embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departure from the spirit and scope of the invention as defined in the appended claims.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations are not expressly set forth herein for sake of clarity.

The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected", or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable, and/or wirelessly interacting components, and/or logically interacting, and/or logically interactable components.

In some instances, one or more components may be referred to herein as

"configured to," "configured by," "configurable to," "operable/operative to,"

"adapted/adaptable," "able to," "conformable/conformed to," etc. Those skilled in the art will recognize that such terms (e.g., "configured to") can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise.

While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., " a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., " a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase "A or B" will be typically understood to include the possibilities of "A" or "B" or "A and B."

With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like "responsive to," "related to," or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. Those skilled in the art will appreciate that the foregoing specific exemplary processes and/or devices and/or technologies are representative of more general processes and/or devices and/or technologies taught elsewhere herein, such as in the claims filed herewith and/or elsewhere in the present application.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

CLAIMS What is claimed is:

1. An electrode, comprising:

a substrate including a body having a first surface opposing a second surface;

a layer of diamond including an inner-side oriented toward at least one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side; and

an active layer on the outer-side of the layer of diamond, wherein the layer of diamond includes polycrystalline diamond and a p-dopant element,

wherein the layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³ and less than 10²³ atoms/cm³, preferably equal to or greater than 10²¹ atoms/cm³ and less than 10²² atoms/cm³, and

wherein the active layer has a composition that includes an element capable of lithium-atom insertion.

2. The electrode of claim 1 , wherein the layer of diamond is a continuous layer deposited directly on the substrate.

3. The electrode of claim 1 , wherein the layer of diamond consists of

polycrystalline diamond and the p-dopant element.

4. The electrode as in any one of claims 1 , 2, and 3, wherein the p-dopant element is selected from the group consisting of boron and aluminum, preferably boron.

5. The electrode as in any one of the preceding claims, wherein the layer of diamond has a thickness of 0.2 μηι to 20 μηι, preferably 2 μηι to 6 μηι, more preferably 4 μηι to 5 μηι.

6. The electrode as in any one of the preceding claims, wherein the substrate has a composition that includes one or more of Si, Mo, Ti, Zr, Hf, V, Nb, Ta, Cr, W, Co, Ni, Y, and Al.

7. The electrode as in one of claims 1-5, wherein the substrate is silicon or molybdenum.

8. The electrode as in any one of the preceding claims, wherein the substrate provides mechanical support to the electrode.

9. The electrode as in any one of the preceding claims, wherein the substrate is flexible.

10. The electrode as in any one of the preceding claims, wherein the composition of the active layer includes Si, Sn, Al, Li or Ge.

11. The electrode as in any one of the preceding claims, wherein a surface of the active layer is a patterned surface.

12. The electrode as in any one of the preceding claims, wherein the electrode is lithiated.

13. The electrode as in any one of the proceeding claims, wherein a doped area of the diamond layer provides a current collector in an electrochemical cell.

14 The electrode as in one of claims 1-11 , wherein the electrode is non-lithiated.

15. A battery, comprising:

a first electrode;

a second electrode; and

an electrolyte,

wherein at least one of the first electrode and the second electrode is the electrode as in any one of the preceding claims.

16. A battery, comprising:

a first electrode;

a second electrode; and

an electrolyte,

wherein the first electrode and the second electrode are each the electrode as in one of claims 1-11 , and wherein the first electrode is lithiated and the second electrode is non- lithiated.

17. A battery, comprising:

a first electrode;

a second electrode; and

a Li-ion electrolyte solution,

wherein the first electrode and the second electrode are each the electrode as in one of claims 1-11 , and

wherein at least one of the first electrode and the second electrode is lithiated.

18. The battery of claim 17, wherein the Li-ion electrolyte solution is a liquid.

19. The battery according to claims 17 or 18, wherein the battery further comprises an ion-conducting separator.

20. The battery of claim 17, wherein the Li-ion electrolyte solution is a solid.

21. The battery of claim 17, wherein the Li-ion electrolyte solution is a gel.

22. A battery, comprising:

a plurality of anodes electrically connected to a negative terminal;

a plurality of cathodes electrically connected to a positive terminal; and a Li-ion electrolyte solution between the plurality of anodes and the plurality of cathodes, wherein a first group of the plurality of anodes and a first group of the plurality of cathodes have electrodes including a first substrate having a body with a first surface opposing a second surface, a first layer of diamond having an inner-side oriented toward the first surface of the substrate and an outer-side opposing the inner-side, a second layer of diamond having an inner-side oriented toward the second surface of the substrate and an outer-side opposing the inner-side; a first active layer on the outer-side of the first layer of diamond, and a second active layer on the outer-side of the second layer of diamond,

wherein a second group of the plurality of anodes and a second group of the plurality of cathodes have electrodes including a second substrate having a body with a third surface opposing a fourth surface, a third layer of diamond having an inner-side oriented toward the third surface of the substrate, and a third active layer on the outer-side of the third layer of diamond,

wherein each of the first layer of diamond, the second layer of diamond, and the third layer of diamond includes polycrystalline diamond and a p-dopant element, wherein each of the first layer of diamond, the second layer of diamond and the third layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³,

wherein each of the first active layer, the second active layer, and the third active layer has a composition that includes an element capable of lithium-atom insertion,

wherein outside of one end of the first group of the plurality of anodes is a cathode from the second group of the plurality of cathodes and one of the first and second active layer of the anode from the first group is oriented toward the third active layer of the cathode from the second group, and wherein outside of one end of the first group of the plurality of cathodes is a anode from the second group of the plurality of anodes and one of the first and second active layer of the cathode from the first group is oriented toward the third active layer of the anode from the second group.

23. A method of manufacturing an electrode, comprising:

depositing a first layer of diamond on a substrate, wherein the substrate includes a body having a first surface opposing a second surface and the deposited first layer of diamond includes an inner-side oriented toward a first one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side; and

forming a first active layer on the outer-side of the deposited first layer of diamond,

wherein the first layer of diamond includes polycrystalline diamond and a p- dopant element,

wherein the first layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³, and

wherein the first active layer has a composition that includes an element capable of lithium-atom insertion.

24. The method of claim 23, further comprising:

depositing a second layer of diamond on the substrate, wherein the deposited second layer of diamond includes an inner-side oriented toward a second one of the first surface of the substrate and the second surface of the substrate and an outer-side opposing the inner-side; and forming a second active layer on the outer-side of the deposited second layer of diamond,

wherein the second layer of diamond includes polycrystalline diamond and a p-dopant element,

wherein the second layer of diamond is doped with the p-dopant element to a doping level equal to or greater than 10²⁰ atoms/cm³, and

wherein the second active layer has a composition that includes an element capable of lithium-atom insertion.

25. The method as in one of claims 22-24, wherein the doping level is equal to or greater than 10²⁰ atoms/cm³ and less than 10²³ atoms/cm³, preferably equal to or greater than 10²¹ atoms/cm³ and less than 10²² atoms/cm³.