Lithium-intercalatable carbon composition and lithium ion battery cell using the same

Abstract

Disclosed is a lithium-intercalatable carbon composition, which includes graphite, a conductive carbon material and a binder. The weight ratio of the conductive carbon material and the graphite is 1: 1 or more. By reducing the graphite content in the electrode, graphite intercalation anomaly can be achieved. This intercalation anomaly turns out to be beneficial on boosting the graphite specific capacity and extend its operation range to sub-zero temperature.

Description

[0001] LITHIUM-INTERCALATABLE CARBON COMPOSITION, ANODE OF LITHIUM ION BATTERY CELL AND LITHIUM ION BATTERY CELL USING THE SAME CROSS REFERENCE TO RELATED APPLICATION

[0002] This application claims the benefit of filing date of U.S. Provisional Application Serial No.

[0003] 63 / 778.564 filed March 27, 2025. The entirety of said Provisional Application is incorporated herein by reference.

[0004] FIELD OF THE INVENTION

[0005] The present invention relates to a lithium-intercalatable carbon composition, an anode of a lithium ion battery cell and a lithium ion battery cell using the same.

[0006] DESCRIPTION OF RELATED ART

[0007] Li-ion batteries (LIBs) have huge impact to the modem society starting from portable energy storage devices and have been making their way towards electric vehicles application. This wide range applications and increasing energy’ demand have pushed LIBs to maximize their storage capability and broadening its operation temperature. However, most LIBs researches are primarily focusing on the development of high specific energy materials while the key parameters of energy efficiency regarding their commercialization are often neglected. Thus, next generation of LIBs require not only novel electrode materials which are capable of providing high capacity and robust architectures, but also able to increase energy efficiency by reducing the production cost as well as operate under wide range temperature. In this regards, the issue related to decayed performance of LIBs at low-temperatures pops out, which becomes one of the main obstacles to restrict their applications at high altitudes or latitudes, and certain defense and space applications. This issue mainly associated to several factors: low ionic conductivity’ of electrolyte, limited Li+diffusivities, and increased interfacial charge-transfer resistant.

[0008] In general, a LIB anode experienced multi-stages process during lithiation: First, the Li-ions in solvated form migrate from the bulk electrolyte to the surface of electrode, which resemble from ionic conductivity of the electrolyte. Second, the Li-ions were released from solvated form (desolvation process) at electrode / electrolyte interface. Third, the desolvated Li-ions yvere furthermigrate through solid electrolyte interphase (SEI) layer and then into the electrode, which corresponds to the SEI resistance and solid-state diffusion process in the bulk material. Notably, all of these process would be significantly impacted by the temperature, especially when the operation temperature dropped to sub-zero. Various approach have been proposed to enhance LIBs performance under low-temperature operation, such as tunning electrolyte composition, developing electrolyte additive, and utilizing series of nanostructure materials. However, improvement of cycling stability associated with charge-discharge behavior at low temperature are remain very difficult.

[0009] On the other hand, graphite has been widely used as an anode material due to its excellent mechanical stability, electrical conductivity, abundant availability, and relatively low cost. However, the limited specific capacity of 372 mA h g’1, by only inserting Li+to LiCe composition between the graphene layers, severely impeded its further application as next generation LIB electrodes. Earlier studies have reported that the specific capacity of graphite can be enhanced beyond LiCe: the higher specific capacities of graphite with 900 mAh g1and 1,660 mAh g1can be achieved by strategies such as heat treatment (pyrolysis at 700 °C) and operated in extreme condition (beyond 100 °C), respectively. Even so, these treatments are considered to be costly thus burden their practical applications. In addition, the mechanism of relatively high specific capacity of graphite is still under debate. Furthermore, several approaches have also been proposed to improve electrochemical performance of graphite under low-temperature operation, such as using mild oxidation, adding metallic particles, chemical doping, and surface coating. Nevertheless, the sluggish desolvation process at interface and slow diffusion in the bulk electrodes was again lead to failure of LIBs at low-temperature.

[0010] SUMMARY OF THE INVENTION

[0011] An objective of the present invention is to provide a novel material that can be applied, for example, in LIB electrodes, offering a desired specific capacity and an extended operating temperature range while reducing production costs.

[0012] In accordance with the foregoing and other objectives, the present invention provides a lithium-intercalatable carbon composition, comprising graphite, a conductive carbon material and abinder, wherein the conductive carbon material has a lower bulk density and smaller particle size than the graphite, and the weight ratio of the conductive carbon material and the graphite is 1 : 1 or more, such as 1.5: 1 or more, 3:1 or more, and preferably is in a range of 1: 1 to 7:1. Compared with high graphite content utilized in existing electrodes, the lithium-intercalatable carbon composition of the present invention can enable Li-carbon coordination beyond LiCe and allow coexistence of Li intercalation species of LiCe, LiC2, and Li-Li covalent bonding within graphite particles during lithiation, namely a Li intercalation anomaly, thereby dramatically enhancing the storage capacity. The reducing graphite weight percentage, while increasing the conductive carbon material (such as carbon black), in the electrode can facilitate capacitive-like behavior and enhance Li+diffusivity in the LIBs, which is expected to improve desolvation Li-ions process and interfacial conductivity of graphite anode at low-temperature operation.

[0013] In the present invention, the conductive carbon material may be a turbostratic carbon black capable of forming a percolation network and typically exhibiting lower bulk density, smaller particle size, higher specific surface area, and lower crystallinity than graphite. More specifically, a nanometer-scale conductive carbon black produced by particle combustion technology' may be utilized as the conductive carbon material. Examples of the carbon black types, which are produced based on the particle combustion technology, include lamp black, furnace black, the Super ™ / ENSACOTMproducts, as well as the carbon black produced as by-products of the shell gasification process such as Ketjenblack ™.

[0014] In the present invention, the total of the graphite and the conductive carbon material may be at least 80 parts by weight per 100 parts by weight of the carbon composition. The graphite may be present in an amount of 40 parts by weight or less (for example, 30 parts by weight or less, 20 parts by weight or less and so on), and the conductive carbon material may be present in an amount of 40 parts by weight or more (for example, 50 parts by weight or more, 60 parts by weight or more and so on), based on 100 parts by weight of the carbon composition. Preferably, the graphite is present in an amount of 10 to 40 parts by weight, and the conductive carbon material is present in an amount of 40 to 70 parts by weight, based on 100 parts by weight of the carbon composition.In the present invention, examples of the binder include, but are not limited to, fluoride-containing adhesive (such as polyvinylidene fluoride), a rubber-based adhesive (such as styrenebutadiene rubber), a combination thereof and the like. Additionally, the carbon composition of the present invention may further include a solvent, such as N-methyl 2-pyrrolidone and the like.

[0015] The present invention further provides an anode of a lithium ion battery cell, including the aforementioned carbon composition. Also, the present invention provides a lithium ion battery' cell, including a cathode; an anode, including the aforementioned carbon composition; a separator disposed between the cathode and the anode; and an electrolyte (such as LiPFe in a mixture of ethylene carbonate and diethylene carbonate) for providing ionic conductivity between the cathode and the anode.

[0016] These and other features and advantages of the present invention will be further described and more readily apparent from the detailed description of the preferred embodiments which follows.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the formulas I to VIII, which are used for the calculation of various parameters. FIG. 2 shows the cyclic voltammogram of GIO, in which the inset figure is the zoomed-in view of the potential range of 0.02-0.3 V.

[0018] FIG. 3 shows the cyclic voltammogram of G80, in which the inset figure is the zoomed-in view of the potential range of 0.02 - 0.3 V.

[0019] FIG. 4 shows the cyclic voltammogram of G20, in which the inset figure is the zoomed-in view of the selected region.

[0020] FIG. 5 shows the cyclic voltammogram of G30, in which the inset figure is the zoomed-in view of the selected region.

[0021] FIG. 6 shows the cyclic voltammogram of G40, in which the inset figure is the zoomed-in view of the selected region.

[0022] FIG. 7 shows the cyclic voltammogram of SP80, in which the inset figure is the zoomed-in view of the selected region.

[0023] FIG. 8 shows the selected charge-discharge profile of G10 at 1C (1C: 372 mAh g'1).FIG. 9 shows the Galvanostatic charge / discharge profile of G20 at selected 100thcharge / dis charge under 1C.

[0024] FIG. 10 shows the Galvanostatic charge / discharge profile of G30 at selected 100thcharge / discharge under 1C.

[0025] FIG. 11 shows the Galvanostatic charge / discharge profile of G40 at selected 100thcharge / discharge under 1C.

[0026] FIG. 12 shows the selected charge-discharge profile of G80 at 1C (1C: 372 mAh g'1).

[0027] FIG. 13 shows the capacity profile of half-cell LIB with different percentage of graphite electrodes.

[0028] FIG. 14 shows the rate performance of G10, G20, and G80.

[0029] FIG. 15 shows the capacity profile and Coulombic efficiency of G10 at 30C.

[0030] FIG. 16 shows the cycling performance at 1C rate of G20 and G80 with closer active material loading.

[0031] FIG. 17 shows the rate performance analysis of G20 and G80 with closer active material loading.

[0032] FIG. 18 shows the electrochemical performance of SP80 a at 1 C rate.

[0033] FIG. 19 shows the Raman spectra of G10 at before and after 100 cycles at 1C with the selected area of G band.

[0034] FIG. 20 shows the Raman spectra of G80 at before and after 100 cycles at 1C with the selected area of G band.

[0035] FIG. 21 shows the selected states of ex-situ XPS analysis on the G20 during charge process, namely QI (3.0 V); Q2 (0.9 V); Q3 (0.2 V); Q4 (0.15 V); Q5 (0.1 V): Q6 (0.05 V); Q7 (0.03 V); Q8 (0.02 V).

[0036] FIG. 22 shows the selected states on the 2ndcharge-discharge process of G80, namely R1 (3.0 V); R2 (0.9 V); R3 (0.2 V); R4 (0.15 V); R5 (0.1 V); R6 (0.05 V); R7 (0.03 V); R8 (0.02 V).

[0037] FIG. 23 shows the Cis XPS spectra of G20 shown at various charge stages.

[0038] FIG. 24 shows the Cis XPS spectra of G80 shown at various charge stages.FIG. 25 shows the Lils XPS spectra of G20 shown at various charge stages.

[0039] FIG. 26 shows the Lils XPS spectra of G80 shown at various charge stages.

[0040] FIG. 27 shows the normalized Li+content in G20 at different charge stages.

[0041] FIG. 28 shows the normalized Li+content in G80 at different charge stages.

[0042] FIG. 29 shows the schematic illustration for the coexistence of two types of Li site in graphite anodes at low and high content, in which graphitic layers are represented by hexagonals; the Li ions and atoms are denoted by open and solid circles, respectively; and covalent bonds between two Li atoms are shown by solid lines.

[0043] FIG. 30 shows the galvanostatic intermittent titration technique profile of GIO.

[0044] FIG. 31 shows the galvanostatic intermittent titration technique profile of G80.

[0045] FIG. 32 shows the Du of GIO during charge process.

[0046] FIG. 33 shows the Du of G80 during charge process.

[0047] FIG. 34 shows the b value as slope function of Log scan rate (v) vs Log peak current (z) for GIO and G80.

[0048] FIG. 35 shows the capacitive and diffusion contribution ratio for GIO at different scan rates. FIG. 36 shows the anodic peak shift of GIO and G80 at various scan rates.

[0049] FIG. 37 shows the Log iovs 1000 / T plot of GIO and G80.

[0050] FIG. 38 shows the Galvanostatic profile of GIO at various temperature range.

[0051] FIG. 39 shows the capacity profile of GIO at various temperature range.

[0052] FIG. 40 shows the Nyquist plots of GIO at 25°C.

[0053] FIG. 41 shows the Nyquist plots of GIO at 0°C and -20°C.

[0054] FIG. 42 shows the Du of GIO at different temperature.

[0055] FIG. 43 shows the b value as slope function of Log scan rate (v) vs Log peak current (z) for GIO at -20 °C.

[0056] FIG. 44 shows the capacitive and diffusion contribution ratio of GIO at sub-zero temperature (-20 °C).

[0057] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSVarious anode electrodes with different graphite content have been fabricated in this study, namely GIO (graphite 10 wt%), G20 (graphite 20 wt%), G30 (graphite 30 wt%), G40 (graphite 40 wt%), G80 (graphite 80 wt%); and an electrode without graphite, SP80, was also fabricated as a control. Various electrochemical methods combined with comprehensive characterization techniques have been performed to elucidate this distinct anomaly associated with the low graphite content.

[0058] Experimental Details

[0059] Materials

[0060] The commercially available natural graphite powder (GN-580L), conductive carbon (Super P®; >99% (metal basis)), poly vinylidene fluoride (PVDF), and IM lithium hexafluorophosphate (LiPFe) in ethylene carbonate (EC) and diethyl carbonate (DEC) (1 : 1 v / v) were purchased from UBIQ Technology Co., Ltd. jV-methylpyrrolidone(NMP; >99%) were purchased from Alfa Aesar (Thermo Fisher Scientific). All the materials were used as received without further purification.

[0061] Electrode preparation

[0062] The graphite electrode with different percentage were prepared by slurry casting method. The recipe graphite electrodes are as follow: GIO (Graphite 10%; Super P 70%; binder (PVDF) 20%);

[0063] G20 (Graphite 20%; Super P 60%; PVDF 20%); G30 (Graphite 30%; Super P 50%; PVDF 20%);

[0064] G40 (Graphite 40%; Super P 40%; PVDF 20%); G80 (Graphite 80%; Super P 10%; PVDF 10%) and as blank sample SP80 (Super P 80%; PVDF 20%). First, graphite powder, conductive carbon and binder were mixed together and stirring at 450 rpm for 24 h in room temperature. Second, the slurry then were casted on the Cu current collector and dried on the hot plate at 60 °C for overnight (12 h). Third, the drying process continued in the vacuum oven at 80 °C for another 8h. Finally, the graphite electrodes were cut in circle with diameter of 12 mm, resulting the electrode area of 1.13 cm2. The average electrode mass loading for G10, G20, G30, G40, G80, and SP80 electrode were maintained 0.76, 0.78, 0.85, 1.00, 2.43, and 0.606 mg cm’2, respectively. These electrodes were then transferred inside of the glovebox for coin cell fabrication.

[0065] Electrochemical measurement

[0066] All electrochemical performances measurement conducted using CR2032 coin cell whichassembled in the glovebox under Argon atmosphere with H2O and O2 concentration were kept <lppm. LIBs half-cell were fabricated in which graphite with different percentage as working electrode and Li metal foil as a counter / reference electrode. Meanwhile, a total of 40 pL of IM LiPFe in mixture of ethylene carbonate (EC) : di ethylene carbonate (DEC) (1:1 v / v) was used as an electrolyte. ACelgard 2325 with 18 mm diameter was used as a separator. The cyclic voltammetry were performed using MultiPalmSens4 electrochemical analyzer with open voltage 0.02 - 3.0 V and scan rate of 0.01 mV s'1. The electrochemical impedance spectroscopy (EIS) analysis were conducted before and after battery cycle using CHI electrochemical workstation model 760e with frequency range from lOmHz to 1MHz and amplitude lOmV. The cells were charged and discharge galvanostatically between 0.02 and 3.0 V using AcuTech battery station systems from AcuTech Systems Co., Ltd. A low temperature reactor Eyela PSL-2500A (Tokyo Rikakikai Co. Ltd) was used to maintain temperature for cycling performance at low temperature condition. Prior the measurement at low temperature, the coincells were prelithiated at 1C rate in room temperature condition. The prelithiated batteries were then kept inside low temperature reactor for 2 h at specified temperature to reach thermal equilibrium prior the measurement. The specific capacity was calculated based on the weight of active materials with respect to different wt% content in the working electrode. Unless it specified, all electrochemical measurements were carried out with at least three replicates to estimates the error and performed in room temperature condition.

[0067] Material characterization

[0068] The X-ray diffraction spectroscopy (XRD) analysis were performed using D2 phaser XRD from Bruker Co., Ltd. The X-ray photoelectron spectroscopy (XPS) was performed using an high-resolution XPS PHI-Quantera II, ULVAC-PHI, Inc. The scanning electron microscope (SEM) were performed using Field-Emission Scanning Electron Microscope (FESEM), Ultra Plus - Carl Zeiss. The Raman spectroscopy were performed using a home-built Raman system with 633nmHe-Ne laser.

[0069] Diffusion coefficient calculation based on GITT method

[0070] The galvanostatic intermittent titration technique (GITT) can be carried out to probe the ion diffusivity of the graphite anodes. The GITT measurement was performed using Squitstatpotentiostats, an Admiral instrument, by alternating current density of 0.1C (1C = 372 mAh g'1) for 20 min with a rest interval of 10 min. Prior to the GITT measurement, fresh coin cells were fully charged under 0.1C and allowed to rest for up to 10 hours. The diffusion coefficient was then calculated by the formula 1, as shown in FIG. 1.

[0071] In the formula I, D is the diffusion coefficient (cm2s'1), T is the current pulse (s), me is the mass of the host material in the electrode (g), VM is the molar volume of the material (cm3mol'1), MB is the molecular weight of the host material (g mol'1), and S is the contact area of the electrolyte and electrode interface (cm2). &and

[0072]

[0073] are the voltage responses over the relaxation and current pulse, respectively.

[0074] Sweep rate voltammetry technique for capacitive contribution

[0075] In the battery system, there are consecutive electrochemical reactions occurs in the electrodes. The sweep rate voltammetry is one of powerful technique to probe those reactions. The total stored charge in a CV curve generally can be separate into three components: (a) the faradaic contribution from the Li+ion insertion process; (b) the faradaic contribution from the charge-transfer process with surface atoms, referred to as pseudocapacitance; (c) the non-faradaic contribution from the double layer effect.

[0076] In addition, the contribution of both types capacitive effects, pseudocapacitance and double layer effect, can be substantial due to the increasing surface area of the electrode. These faradaic contribution from insertion process (diffusion control) and capacitive effects can be characterized using CV data at various scan rates and expressed by the formula II, as shown in FIG. 1.

[0077] In the formula II. i is current response to the scan rate v, while a and b are constants. The b value can be obtained from the slope of log i vs log v. In addition, if the b value close to 0.5 would indicate half-infinite linear diffusion controlled process, meanwhile b value close to 1 indicates the current is surface controlled. Since the b value is the sum of faradaic response of diffusion controlled and capacitive effects, a closer examination from sweep rate voltammetry can be applied to quantity7the capacitive effects (kv) and diffusion controlled behavior (fov1 / 2) by the formula III, as shown in FIG. 1.In the formula III, the k\ and k values can be determined by plotting i / v1 / 2vs v1 2Theoretical capacity

[0078] In the battery system, the theoretical capacity of any active material can be estimated by the formula IV (Faraday7law), as shown in FIG. 1.

[0079] In the formula IV. n is number electron transferred, F is Faraday constant, and

[0080]

[0081] is molecular weight of active material. According to Faraday's law, the theoretical capacity of LiCe and LiC2 were estimated to be 372 and 1117 mAh g'1.

[0082] Diffusion coefficient calculation based on EIS spectra

[0083] EIS is a powerful tool to investigate electrical properties of materials surface in association with physicochemical processes such as charge transfer of electronic and ionic charge carriers, mass transport through diffusion and convection. The Nyquist plots typically can be divided into three sections, namely high, mid and low frequency regions. The high frequency region reflected the conduction through electrolyte, separator and wires. The mid frequency region is related to the charge transfer and the kinetic reactions. The low frequency region in which usually featured by 45° slope, represents the diffusion limited region in the solid phase and is ty pically characterized by the Warburg impedance. Basically, there are two formulas V and VI, as shown in FIG. 1 , that define Warburg impedance.

[0084] In the formulas V and VI, Z' and Z"are real and imaginary impedance, respectively, co is the angular frequency and G is the Warburg coefficient. Therefore, The Warburg coefficient (a) can be 1

[0085] determine by the slope of Warburg plot (Z' vs l / to ). Meanwhile, the relationship of Warburg coefficient (o) and the diffusion coefficient is given by the formula VII, as shown in FIG. 1.

[0086] In the formula VII, R is ideal gas constant, T is absolute temperature, n is the number of electron transferred, F is Faraday’s constant, A is the area of the electrode, Do and D / < are the diffusivity' of oxidation and reduction species, respectively. Then Co and CR are the concentration of oxidation and reduction species, respectively. In addition, because of the fact that only Li+which moving inside of graphite electrode, the Warburg coefficient (a) can be simplified by the formula VIII, as shown in FIG. 1.In the formula VIII, Di i and CL; are the diffusion coefficient and concentration of Li Result and discussion

[0087] In order to probe the behavior of different percentage graphite anodes during insertion / extraction of Li+, series of electrochemical measurements have been firstly applied in room temperature condition. First, cyclic voltammetry' (CV) measurement has been performed to observe the redox potential of different percentage graphite anodes. As shown in FIGS. 1 and 2, four major reduction peaks are monitored on the cathodic scan of GIO (FIG. 2), while G80 (FIG. 3) exhibited only two major peaks. These multiple reduction peaks on the cathodic scan represented with multistages of Li+insertion during electrochemical processes. The first peak at ~0.9 V is preferential to the initial stage of lithiation process which is began by Li+adsorption on the most outer layers of graphite due to higher conductive environment in the electrode. This distinct Li+uptake in the graphitic carbon materials at relatively higher voltage than 0.25 V has also been observed in the previous reports. Furthermore, the second peak at 0.2 V can be assigned as the follow up process from Li+adsorption process. At this phase, Li+starts to insert on the most outer layer of graphite, which could be possibly signed as stage IV intercalation (30C + Li<s> LiCso). This process is followed by continuous Li+intercalation into more inner layers of graphite, as indicated from the minor peak at 0.15 V, which is an indication of stage III intercalation (LiCv, + Li<s) 2LiCis). The third and fourth peaks located at 0.1 and 0.05 V are attributed to the further Li+intercalation in graphite layers that were presumably' linked as deep intercalation stage II (1 / 2 LiCis + Li(S) 3 / 2 LiCs) and stage I (6C + Li(S> LiCe), respectively.

[0088] On the contrary only two major peaks can only be monitored for G80 (FIG. 3) at 0.19 and 0.08 V during cathodic scan, which could be associated to stage IV and stage II intercalation, respectively. The missing reduction peak of -0.9 and 0.05 V could indicated that a minimum utilization of interlayer graphite under high percentage in the electrode (G80). Additionally, the appearance of four major peaks in cathodic scan can also be observed in G20, G30 and G40 (FIGS.

[0089] 4-6), indicating an excellent occurrence of Li+intercalations into graphitic layers at low graphite content in the electrode. Notably, no redox peaks can be monitored on the SP80 electrode during CVmeasurement (FIG. 7), indicating that no specific redox reaction happen in this electrode during electrochemical process. This further implies that most of electrochemical responses in the CV were contributed from redox reaction within graphite particles.

[0090] In agreement with the CV results in FIG. 2, the galvanostatic charge / discharge profile of GIO (FIG. 8) denoted four different plateaus at 0.9, 0.2, 0.1 and 0.05 V. which correlates respectively to their Li+intercalation stages during lithiation process. Interestingly, this four plateaus brought significant increase in capacity' for G10 up to 2200 mAh g’1after 100 cycle at 1C. This outstanding specific capacity7is nearly six times higher than that of conventional graphite (372 mAh g’1) via LiCe formation. Additionally, this four voltage plateaus can also be observed on the G20, G30, and G40, bringing the Li+storage capacity beyond 372 mAh g’1(FIGS. 9-11). On the other hand, G80 only showed two different plateaus at 0.2 and 0.1 V with the specific capacity of 230 mAh g’1at 1C (FIG.

[0091] 12). Notably, as applied the same charge-discharge rate of 1C, G10 exhibited a significantly longer time (~6 hours) to get fully lithiated stage at 0.02 V (FIG. 8). while G80 only requires 0.6 hours (FIG.

[0092] 12). This obvious time difference also suggests that reducing graphite content in the electrode could lighten graphitic layers utilization thus brought a significant impact on achieving extremely high specific capacity7. Following the superior performance of G10, batteries with G20, G30, G40 and G80 exhibited capacity of -980 mA h g’1, -580 mA h g’1, -340 mA h g’1and -230 mA h g’1, respectively (FIG. 13). Furthermore, the extreme rate capability7has also been demonstrated for G10 and G20 up to 30C (FIG. 14). Furthermore, G10 possessed an extremely high rate capability of -1430 mA h g'1at a relatively high current rate of 30C with excellent stability for up to 2000 cycles (FIG.

[0093] 15).

[0094] To verify the substantial improvement on graphite specific capacity under low percentage, the G20 with the increase active material loading into the electrode up to 1.80 mg cm’2was prepared. While, the loading of G80 was reduced to 1.19 mg cm’2. Surprisingly, the G20 electrode with higher loading of 1.80 mg cm’2still hold a high specific capacity7of 840 mAh g’1at 1C (FIG. 16), while G80 can only deliver capacity of 225 mA h g’1. Moreover, similar trend can also be seen in the rate performance (FIG. 17) where the G20 with high material loading could deliver specific capacity of211 mA h g'1under extremely high current rate of 30 C. Additionally, the specific capacity generated from SP80 electrode was found to be ~71 mAh g'1under 1C (FIG. 18), indicating that the capacity contributed from the conductive carbon is significantly low compare with the performance of graphite performance under low percentage (GIO and G20). This low specific capacity of SP80 was consistent with the CV (FIG. 7), where no specific redox reaction observed during electrochemical process. Therefore, it suggests that graphite intercalation anomaly could possibly occurred under lower active material percentage within the electrode, thus extent and enhance graphite specific capacity7beyond 372 mAh g'1(traditional LiCe intercalation).

[0095] To examine the effect of graphite content on the Li+storage mechanism, ex-situ XRD measurements of low graphite content (G20) electrode and high graphite content (G80) electrode were performed to evaluate their structural evolution during Li+insertion / extraction. Surprisingly, a distinct structural evolution during Li1insertion / extraction can be observed for low graphite content of G20 than that of G80 (high graphite content). During the lithiation process from 0.23 to 0.14 V, the diffraction peak of (002) at 26.3° (0.23 V) shifts to a lower value of 25.8° (0.14V), implying that the graphite interlayer-spacing (^ / -spacing) increases from 3.33 A (pristine) to 3.37 A (0.23V) and then 3.44 A (0.14V). This increasing ^ / -spacing is a result from early lithiation process associated with the formation of Li+intercalation stage IV (LiCso) and stage III (LiCis), respectively, after Li+adsorption process on the outer layer of graphite. Furthermore, a twin diffraction peak associated with the cZ-spacing of 3.44 and 3.49 A, respectively, is obtained at 0.12 V, indicates the transition from Li+intercalation stage III to stage II during the further lithiation process. In contrast, these intercalation stage III and II of G80 electrode can only be obtained at deeper lithiation process at 0.07 V. This suggests that low graphite content lighten interlayer utilization than that of higher content. Furthermore, the G20 electrode with a d-s pacing of 3.68 A (24.1°) is obtained at 0.08 V, corresponding to the deep Li+intercalation of stage I (LiCe formation) during the lithiation process. On the contrary7, the intercalation stage I can only be slightly observed at 0.02 V in the G80 electrode (full charge state), along with major contribution of stage II. This phenomena further suggests that the low7graphite content electrode can be fully lithiated and forms LiCe at higher voltage of 0.08 V,while the higher graphite content electrode at the full charged state of 0.02 V is dominated by stage II with minor contribution of stage I, indicating a lighten graphite interlayer utilization. Additionally, the diffraction peak with a d-s pacing of 3.68 A on the G20 gradually become dominant, along with the disappearance of diffraction peak of 25.38° ( / / -spacing of 3.49 A), as the lithiation process proceed to a deeper potential from 0.07 V to 0.02 V (full charge stage). This indicates that most of graphite interlayer in the G20 electrode has been intensively escalate to accommodate large Li+intercalation, than that of G80. Therefore, these graphite intercalation anomaly based on the ex-situ XRD studies of G20 and G80 implies that further lithiation process beyond the Li+intercalation stage I (LiCe) possibly taken place during deep charge process of G20 from 0.07 V to 0.02 V (full charge stage), thus significantly contribute in boosting the capacity of graphite under low percentage. Moreover, the reaction process is reversible during delithiation process.

[0096] Additionally, field emission scanning electron microscope (FESEM) analysis was performed to probe the morphological changes of graphite particles during electrochemical process. The result of the FESWM analysis showed that the interlayer of graphite in G20 was significantly expanded at full-lithiation state (0.02 V). This interlayer expansion could be ascribed due to an intensive Li-ion insertion during charge process, which consistent with the ex-situ XRD results, where t / -s pacing of graphite enlarged from 3.37 (pristine) to 3.68 A (at full-charge state of 0.02V). Meanwhile, at the full-discharge state (full de-lithiation at 3.0 V), the well-defme graphite interlayer can be monitored with a minimum expansion. This phenomena is suggesting a reversible expansion / relaxation phenomena of graphite interlayer during electrochemical process, and is consistent with the ex-situ XRD results. Notably, a similar well-defme graphite interlayer expansion can also be monitored at G20 even after 100 cycles, while no significant changes can be observed on G80. These distinct morphological changes further confirmed an intercalation anomaly of graphite under ultra-low content anode. Furthermore, a distinct graphite morphological evolution is observed in the ex-situ Raman spectroscopy of G10 and G80 at before and after 100 cycles (FIGS. 19 and 20). As shown in FIGS. 19 and 20, typical graphite C-C bonding properties, sp3(D band) and sp2(G band) carbon, can be observed for both G10 and G80. The D band showed no significant changes in G10 and G80 after100 cycles, though, the G band indicated significant peak deformation for GIO. As depicted in FIG.

[0097] 19, the G band peak of GIO, which originally located 1598 cm’1at before cycle, was transformed into two overlapped peaks namely G+(1608 cm’1) and G’ (1576 cm’1). However, the G band of G80 was only slightly shifted from 1590 to 1595 cm’1after 100 cycles (FIG. 20). The shifting of G band towards the higher wavenumber G+(-1600 cm’1) has been recognized from the result of intensive interlayer expansion due to insertion species that formed graphite intercalation compound (GIC) and increased the C=C bond length. Meanwhile, the G band shift negatively to a lower wavenumber G’ (1576 cm’1) indicated the transformation of sp2carbon bonding configuration or formation of a shorter sp2chain. This ex-situ Raman analysis further implied that the graphite under low content in the electrode experienced massive interlayer expansion and structural transformation during cycling process, due to intensive Li+insertion into interlayer of graphite. This observation was again in good agreement with the ex-situ XRD and FESEM analysis.

[0098] To gain a further understanding on the chemical bonding during electrochemical process, the ex-situ XPS was also performed to evaluate chemical compositions at selected states during 2ndlithiation process, namely states Q1-Q8 for G20 (FIG. 21) and R1-R8 for G80 (FIG. 22). The ex-situ XPS analysis have been summarized and presented in FIGS. 23 and 25 for G20 and FIGS. 24 and 26 for G80, respectively. As presented in (FIG. 23), the C 1 s spectra at the initial state, 3.0 V (QI) showed specific binding energy (BE) of C=C, C-C, C-O, C=O, and CCh2’ at 284.21, 284.76, 286.05, 287.7, and 289.05 eV, respectively. ABE associated with the ti-tt satellite peak can also be observed at 290.19 eV. Furthermore, an additional BE at 283.2 eV associated with C-Li binding started to appear at 0.9 V (Q2) and kept until Q8, indicating the lithiation process (FIG. 23). Notably, the 71-71 satellite peak at 290.19 eV disappeared as the Li+intercalation reached 0.05 V (Q6) (FIG. 23), indicating that the 7t-7t interaction between basal planes of graphene were fully utilized to capture Li+during intercalation thus results in a weakened interlayer bonding and increased d-s pacing of graphite, which is in good agreement with the ex-situ XRD of G20. On the contrast, the n-n satellite peak of G80 is visible from initial state R1 to R7, along with an additional BE at 283.2 eV for C-Li binding started to appear from R3 (FIG. 24), indicating that the abundant TI-TT electrons in G80 are not occupied by Li+during chargeprocess. The Cis spectra illustrates that the graphitic interlayers in low graphite content (G20) electrode are fully utilized during Li+intercalation than that of high graphite content electrode (G80).

[0099] This unique behavior could be possibly responsible for boosting the battery performance.

[0100] In good agreement with Cis spectra, the Lils spectra of G20 showed the LiCso and LiCis formation with BE of 54.02 and 53.60 eV at 0.9 V (Q2) (FIG. 25), which has been recognized as Li+adsorption on the graphite surface (FIG. 2). This phenomenon suggested that Li+started to intercalate in the outer layer of graphite at 0.9 V (Q2) and results in stage IV and stage III intercalation via formation of LiCso and LiCis during this adsorption process. Furthermore, this process is consistent with ex-situ XRD of G20 ranged from 0.23 to 0.17 V, in which graphite -spacing increased from 3.33 A (pristine) to 3.37 and then 3.44 A. As the applied potential is lowered to 0.2 V (Q3), the new BE at 53.40 eV for LiC appeared along with L1C30 and LiCis formation (FIG. 25), which were no longer observable after 0.05V (Q5). Interestingly, the BE at 53.35 eV for LiCg (stage I) begin to form at 0.1 V (Q5), which is in good agreement with ex-situ XRD, denoting a better utilization of graphite interlayer for G20 electrode than that of G80. Furthermore, an additional BE close to the LiC2 formation appeared at 53.10 eV along with the existence of LiCn and Li CV when the applied potential reached 0.05 V (Q6; FIG. 25). Importantly, when G20 electrode was fully charged at 0.02 V (Q8), the BE of Li-Li (Li°; 52.3 eV) emerged along with LiCe and LiC2 formation. This co-existing three different Li intercalation species at fully charged state in low graphite content electrode (G20) could be responsible for significantly improved Li+storage capability. The appearance of Li° BE could be linked to the increased Li metallic character in the state of L1C2. In the LiC2 configuration, it was assumed that all the benzene units from the basal plane of graphene were filled with Li ions. Therefore, the continuous insertion of Li+in LiC2 configuration will further push the existing intercalated Li ions getting close one to another, thus increased its metallic character and form Li-Li covalent bonding.

[0101] The ex-situ XPS study manifest that further Li intercalation process beyond Li CG can be found in the lower graphite percentage (G20) via formation of LiC2, indicating an graphite intercalation anomaly under low content electrode. In this intercalation anomaly, a large interlayer expansion of 3.68 A at the stage of 0.08 V-0.02 V has opened a channel for further Li intercalation process to formLiC2. This is in good agreement with the previous study that the superdense Li state (LiC2) can be formed in the graphitic layers with ^-spacing of ~3.7 A, which is close to the -spacing of G20 at 0.02V. On the contrary, Lils spectra of G80 in FIG. 26 showed a different Li intercalation behavior than that of G20 (FIG. 23 and 25). The formation of LiCso and LiCis in G80 started from 0.2 V (R3) and remained until fully charged at 0.02 V (R8), while LiCn began to emerge from R4 and dominate in the Li intercalation stage along with the additional LiCe formation at R8 (FIG. 26). This behavior was consistent with the ex-situ XRD spectra of G80. More importantly, the LiC2 and Li-Li covalent binding cannot be observed in Lils spectra for G80 electrode, suggesting a different Li+intercalation mechanism to G20 electrode. The Lils spectra of G80 again confirmed that the behavior of graphite particles changes significantly as the graphite content in the electrode decreases.

[0102] Moreover, FIG. 27 depicted the Li-C binding evolution of G20 at different charging states (Q1-Q8) with appropriate portion contributed in the specific charge, which clearly implies the coexisting three Li intercalation species of LiCe. LiC2. and Li-Li covalent bonding formation taken place during lithiation process. However, Li-C binding evolution of G80 in FIG. 28 reveals that LiCi2 species dominated Li storage, followed by LiCe formation at the full charge state (R8). This distinct intercalation behavior in low and high graphite content electrode manifesting that graphite intercalation anomaly could occurred and boosted the specific capacity of graphite anode. Furthermore, FIG. 29 shows schematic illustration of distinct graphite intercalation behavior under different content in the electrode. As shown in FIG. 29, graphite particles experience Li+intercalation anomaly, where most of graphitic layers were utilized to accommodate superdense Li+states under low graphite content electrode. In this superdense Li+intercalation process, three Li intercalation species of LiCe, LiC2, and Li-Li covalent bonding formation co-existed within graphite particles and consequently improved the storage capability. On the contrary, graphite experience dilute Li+intercalation state, where LiCn species dominated Li storage, followed by LiCe formation.

[0103] In order to reveal the feasibility of low graphite content as an alternative solution for low-temperature LIB, the galvanostatic intermittent titration technique (GITT) was employed for G10 and G80 at 0.1 C rate. FIGS. 30 and 31 shows the typical galvanostatic profile of the G10 and G80 anodesduring GITT measurement, respectively. Interestingly, GIO has significantly faster Li+diffusion coefficient (Du) of ~1O'09- IO'10cm2s'1than that of G80 (~10'°9- 10'14cm2s'1) during lithiation process (FIGS. 32 and 33). As shown in FIG. 32, the Du of GIO dropped up to nearly 10'10cm2s'1at potential of ~0.ll and 0.8 V. due to the formation of more compact Li-C species of LiCn and LiCe. respectively. On the contrary, the Du of G80 dramatically slumped up to -10'11and ~10'14cm2s'1at potential of ~0.ll and 0.8 V (FIG. 33), indicating a huge barrier for Li+mobility in the G80 during lithiation process. Additionally, a small decrease Du of G10 can be monitored at potential -0.05 V (FIG. 32), which could be ascribed to formation of superdense Li intercalation (LiC2). This further suggests that G10 could provide a significant faster Du than that of G80 during phase transitions. This phenomenon could be attributed to the minimum resistances between graphite particles inside of electrode and electrolytes due to higher conductive environment that allowed a rapid electron transfer, therefore accelerate Li1transport and improve LIB performance. It was confirmed that, the increased active material amount within the electrode could impinges the ion transport across the electrode during charge and discharge process. It should be noted that the solid-state Li+diffusion acts as a bottleneck for insertion-type materials during the charge storage process, especially at low-temperature. The increasing conductive environment by reducing the graphite content in G10 enables the fast solid-state diffusion of Li+in the bulk electrode, which circumvents the limiting rate of commonly used electrode architecture.

[0104] To further probe the ion migration kinetics, a sweep rate CV has been carried out with scan rate ranging from 0.1 to 0.7 mV s'1for both G10 and G80. According to the power-law relation from sweep rate voltammetry, the b value of G10 and G80 were found 0.61 and 0.27 (FIG. 34), suggesting the ion migration in G10 was contributed from diffusion control process and pseudocapacitive behavior simultaneously, while the G80 was only contributed from diffusion controlled process. Further analysis of b value revealed a positive slope of ki (0.1742) and 39% contribution from capacitive effects in the G10 electrode at higher scan rate of 0.7 mV s'1(FIG. 35). This contribution gradually decreased up to 15% when the scan rate is lowered to 0.1 mV s'1. This phenomena again confirmed that the Li+storage kinetics was controlled by diffusion control process andpseudocapacitive behavior simultaneously. The synergic contribution of both diffusion and pseudocapacitive behavior could further explain the superior performance of low graphite content. If it is assumed that the highest capacity of GIO (2200 mA h g’1) is generated from the contribution of both pseudocapacitive and diffusion controlled process (intercalation), a total capacity of -880 mAh g’1(40%) can be counted as a resulted from capacitive behavior and -1320 mA h g’1(60%) contributed from diffusion controlled process (intercalation). Hence, it suggests that a maximum capacity7of 1320 mAh g’1is achieved via Li intercalation in between interlayer of graphite, which is close to the formation of LiC2.

[0105] Another interesting feature is that the anodic peak of G10 was not significantly shifted at various scan rates (FIG. 36), which also identify as combination of diffusion and pseudocapacitive behavior. This such feature has been reported can help overcome the sluggish solid-diffusion process in the electrolyte / electrode interphase, which is considered as one of the most impeding factors for the operation of LIBs at low temperature. Additionally, the electrochemical impedance spectroscopy (EIS) has been employed to evaluate the relationship between exchange current (z0) and charge transfer resistance at electrode interfaces Ret) under different temperatures. This correlation help to understand and estimate the activation energy of active materials by using followed Arrhenius equation: io = RT nl-Rci. and io=Aexp(-Ea / RT) , where A is the temperature-independent coefficient, R represents the gas constant, T is the operating temperature (K), n represents the number of electrons being transferred, F is the Faraday constant, and

[0106]

[0107] represents the apparent activation energy of the active materials in the electrode. Taking these equations, the activation energy’ is estimated as: Ea = -RklnlO, where k is the slope of the fitting line of Arrhenius plots (LoglOio as a function of 1000 / T). As shoyvn in FIG. 37, the Eaof G10 and G80 electrode yvere estimated to be 25.93 and 31.04 kJ mol’ respectively. This indicates that reducing graphite content, while increasing the conductive environment in the electrode, could minimized the graphite particle activation energy to store the Li+.

[0108] Benefiting from the unique features of high diffusion coefficient and additional pseudocapacitive contribution as yvell as the reduction of activation energy on low graphite content, the G10 can overcome the sluggish desolvation process and slow diffusion in LIBs under loyv-temperature environments. To clarify this point, the electrochemical performance and kinetical study of GIO at low temperatures were performed and investigated in details, presented in FIG. 38. FIG.

[0109] 38 showed the galvanostatic charge-discharge profde of GIO at various temperature after 100 cycles. When the battery was operated 0°C, GIO can deliver a capacity of 1250 mAh g1, corresponding with a high capacity retention of 62.5 % (1250 mAh g-1 / 2200 mAh g'1= 62.5%). This capacity drop could be resulted from sluggish Li+diffusion across electrolyte-electrode at low temperature. Surprisingly, when the battery' reached at even lower temperature of -20°C, the specific capacity of G10 was still kept at 1100 mA h g'1(50% capacity retention), indicating a superior performance at sub-zero temperature. Furthermore, no significant changed can be monitored on the galvanostatic profile of G10 at low-temperature operation, suggesting a high material stability. In good agreement with the galvanostatic profile, the capacity profile indicates a reduced storage capability' from 2200 mAh g'1to 1250 mAh g'1is observed when the operation temperature was lowered from 25°C to 0 °C (FIG.

[0110] 39), respectively, due to limited Li diffusion at low temperature. Notably, the Li storage capacity was only slightly decreased from 1250 mAh g’1to 1100 mAh g'1, when the operation temperature was set at -20 °C. A capacity fluctuation is observed when the battery was operated at 0 °C, and became relatively steady cycling performance at -20 °C. This capacity' fluctuation can be associated with the increasing electrolytes viscosity under low-temperature operation. As the operating temperature at 0 °C, the movement of EC molecules is significantly hindered, due to a higher freezing point (~35 °C), than that of DEC at -43 °C, thus creating a binary phase condition in the electrolytes. This condition could possibly disturb and create ion flow fluctuation in the electrolyte during charge / discharge process across the cycles, thus result in a significant capacity fluctuation at 0 °C. However, this binary phase become minimum at -20 °C. as the DEC molecules movement is further minimized, therefore a more steady cycling performance could be achieved with the decreasing specific capacity up to 1100 mAh g’1(FIG. 39).

[0111] To probe the kinetical phenomena under low-temperature operation, the EIS study was again applied under different temperature. As shown in FIGS. 40 and 41, a significant increase of chargetransfer resistant can be monitored when the operation temperature was lowered from 25 °C to -20°C, suggesting an increased interfacial charge-transfer at low-temperature. Furthermore, the Du of GIO has also showed significant decrease from ~1O’10cm2s’1to ~10’14cm2s’1as the operation temperature drops from 25 °C to 0 °C (FIG. 42), indicating a limited Li diffusion under low temperature. Interestingly, the Du was only slightly shifted to a lower value when the operation temperature reached sub-zero level (-20 °C; FIG. 42). This indicated that the high conductivity on the bulk electrode is beneficial for maintaining the fast charge-transfer properties, Li+diffusion ability, and battery' performance at sub-zero temperature. In addition, sweep rate CV was again employed to dig out the charge mobility7under sub-zero temperature. Furthermore, the b-value at -20°C was found to be 0.81 (FIG. 43), an 0.2 value increased from that of in 25 °C (0.61; FIG. 34). This suggesting an increased pseudocapacitive contribution during charge-discharge process at -20 °C. The quantitative analysis from total charge stored during sweep rate test at -20 °C further revealed that a high of 72% pseudocapacitive contribution is accumulated at higher scan rate of 0.7 mV s’1, along with significant low of diffusion contribution (28%; FIG. 44). This pseudocapacitive contribution was then gradually decreased up to 52% at slow scan rate of 0.1 mV s’1, along with increasing diffusion contribution to 48%, indicating the simultaneously contribution of both pseudocapacitive and diffusion during charge-discharge process. During lithiation, the pseudocapacitive feature of G10 at low temperature could promote the desolvation process of Li+from electrolyte / electrode at the interphase, while, the fast ions diffusion on G10 accelerated the migration of Li ions in the bulk electrode. This synergistic contribution of high diffusion coefficient in the bulk electrode and pseudocapacitive contribution turns out to be a perfect combination, which greatly facilitates G10 with the excellent low temperature performance.

[0112] Conclusion

[0113] In the present invention, graphite intercalation anomaly under its low content within the electrode was observed. This intercalation anomaly turns out to be beneficial on boosting the graphite specific capacity and extend its operation range to sub-zero temperature. It is believed that this could be an efficient and effective approach to reduce the production cost of commercial graphite anode in the LIBs. Harnessing the unique feature of lighten interlayer utilization due to fast diffusion,pseudocapacitive contribution, and lower activation energy, low graphite content electrode demonstrated an outstanding specific capacity and ultra-high rate capability of commercial graphite. The use of low graphite content anodes, GIO and G20, leads to superior specific capacities of 2200 and 980 mAh g1, respectively, exceeding the state of the prior art graphite anode (372 mAh g1) at room temperature. Surprisingly, the GIO anode possess an extremely high capacity of 1100 mAh g'1as operated at sub-zero temperature (-20 °C). This by far is the highest specific capacity recorded at -20 °C. Furthermore, the G10 anode possess an extremely high capacity of -1430 mAh g'1at ultra-high current rate of 30C with excellent stability for up to 2000 cycles. The systematical spectroscopy analysis reveals that the origin of this extraordinary performance is due to the synergetic interplay of capacitive contribution and successful formation of superdense Li+intercalation between graphite interlayers. In addition, the perfect combination of high diffusion coefficient in the bulk electrode and pseudocapacitive contribution as well as the reduce graphite activation energy in the electrode greatly enhance the battery performance at low-temperature operation. These results demonstrate the simplest and cheapest attempt to optimize graphite interlayers for Li+storage, pushing the Li'carbon coordination beyond LiCe and unlocking hidden potential of graphite at low-temperature.

[0114] The above examples are intended for illustrating the embodiments of the subject invention and the technical features thereof, but not for restricting the scope of protection of the subject invention. Many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. The scope of the subject invention is based on the claims as appended.

Claims

What is claimed is:

1. A lithium-intercalatable carbon composition, comprising graphite, a conductive carbon material and a binder, wherein the weight ratio of the conductive carbon material and the graphite is 1 : 1 or more, and the conductive carbon material has a lower bulk density and smaller particle size than the graphite.

2. The lithium-intercalatable carbon composition of claim 1, wherein the weight ratio of the conductive carbon material and the graphite is 1.5: 1 or more.

3. The lithium-intercalatable carbon composition of claim 1, wherein the weight ratio of the conductive carbon material and the graphite is 3: 1 or more.

4. The lithium-intercalatable carbon composition of claim 1, wherein the weight ratio of the conductive carbon material and the graphite is in a range of 1: 1 to 7:1.

5. The lithium-intercalatable carbon composition of anyone of claims 1 to 4, wherein a total of the graphite and the conductive carbon material is at least 80 parts by weight per 100 parts by weight of the lithium-intercalatable carbon composition.

6. The lithium-intercalatable carbon composition of any one of claims 1 to 5, wherein the graphite is 40 or less parts by weight and the conductive carbon material is 40 or more parts by weight per 100 parts by weight of the lithium-intercalatable carbon composition.

7. The lithium-intercalatable carbon composition of claim 6, wherein the graphite is 30 or less parts by weight and the conductive carbon material is 50 or more parts by weight per 100 parts by weight of the lithium-intercalatable carbon composition.

8. The lithium-intercalatable carbon composition of claim 6, wherein the graphite is 20 or less parts by weight and the conductive carbon material is 60 or more parts by weight per 100 parts by weight of the lithium-intercalatable carbon composition.

9. The lithium-intercalatable carbon composition of claim 6, wherein the graphite is 10 to 40 parts by weight and the conductive carbon material is 40 to 70 parts by weight per 100 parts by weight of the lithium-intercalatable carbon composition.

10. The lithium-intercalatable carbon composition of anyone of claims 1 to 9 which isconfigured to allow Li-carbon coordination beyond LiG, during lithiation.

11. The lithium-intercalatable carbon composition of anyone of claims 1 to 9, which is configured to allow coexistence of Li intercalation species of LiCs, LiC2, and Li-Li covalent bonding within graphite particles during lithiation.

12. The lithium-intercalatable carbon composition of anyone of claims 1 to 11, wherein the conductive carbon material is carbon black.

13. The lithium-intercalatable carbon composition of claim 12, wherein the conductive carbon material is a nanometer size-carbon black produced by particle combustion technology.

14. The lithium-intercalatable carbon composition of anyone of claims 1 to 13, further comprising a solvent.

15. The lithium-intercalatable carbon composition of claim 14, wherein the solvent is NMP (N-Methyl 2-pyrrolidone).

16. An anode of a lithium ion battery cell, comprising the lithium-intercalatable carbon composition of anyone of claims 1-15.

17. A lithium ion battery7cell, comprising:a cathode;an anode, including the lithium-intercalatable carbon composition of anyone of claims 1-15; a separator disposed between the cathode and the anode; andan electrolyte for providing ionic conductivity between the cathode and the anode.

Images