EEStor Phase 9 Test Results for CMBT-Glass and CMBT-Polymer Hybrid Capacitors

EEStor Corporation (TSXV:ESU), developers of high energy density, solid-state capacitors, announce

the results of independent third party testing of hybrid capacitors, made with EEStor’s proprietary

Composition Modified Barium Titanate (CMBT) powder combined with glass and polymer matrices.

EEStor has reported performance previously on the CMBT-Polymer hybrid capacitors in Phase 6 and

on the CMBT-Glass hybrid capacitors in Phase 7 and 8. EEStor has made significant advancements in

both systems. The reader eager to understand the technical data disclosed in this white paper is invited

to consult the primer Understanding EEStor Parameters, available on EEStor’s website.

EEStor’s CMBT-Glass hybrid dielectrics have been advanced over prior phases in many

different aspects.

Dielectric layers made of CMBT alone, as used in the K-square and MLCC detailed in EEStor MLCC

white paper, sinters at above 1300°C. Therefore, it requires precious metal to be used as electrodes

during manufacturing. However, the usage of CMBT-Glass hybrid dielectrics, rather than CMBT alone,

lowers the sintering temperature below 1150°C, allowing the use of much lower cost base metal

electrodes. All the CMBT-Glass hybrid dielectrics in this report were sintered below 1150°C. It has been

well established that the addition of glass to the successful manufacturing process of MLCC recently

disclosed by EEStor would be straight forward.

Since Phase 7, EEStor’s CMBT-Glass hybrid dielectrics have been reported featuring high

relative permittivity (κ) at low field (κ > 10,000 at a field > 1 V/µm). The main challenge of EEStor’s

R&D program has been to improve its dielectric material so that it keeps the high relative permittivity

(κ) as the field is increased. Indeed, if the κ stays nearly constant, the energy density (ED) of the

material grows at the square of the increase of the field. The ED is a measure of the quantity of material

required to make a capacitor of a certain capacitance and voltage, and thus, for material and process

costs comparable to the rest of the industry, the best metric of profitability of the dielectric.

For Phase 9 formulations, EEStor has been focusing on lowering the change in κ with higher

field, called the DC bias characteristics of the dielectric. Mixing more glass with CMBT lowers the

relative permittivity (κ) of the resulting layer of dielectric. Phase 9 samples have a lower initial κ than

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phase 8 samples. However, phase 9 samples achieve much higher κ at higher field than those of Phase

8 (the κ starts saturating at higher field). An example of this advancement is demonstrated by phase 9

samples 432-6 and 434-5a in Intertek Phase 9 report, phase 9 samples demonstrate a near doubling

of κ with field over phase 8 samples such as 344-2b.

Table 1. Phase 8 and Phase 9 Permittivity at voltage

Sample Relative Permittivity (κ) Voltage (V/µm)

Phase 8 344-2b 407 22.2*

Phase 9 sample 432-6 783 22.2

Phase 9 sample 434-5A 792 22.2+

*(interpolated from 479 at 15.6 V/µm and 394 at 23.4V/µm) + (interpolated from 854 at 18.5 V/µm and 699 at 27.8V/µm)

The result of this near doubling of κ with field is that EEStor’s size advantage over existing

capacitor technology (documented in Phase 8 and subsequent marketing Press Releases) has

dramatically increased. In Phase 8, a Kemet 40 volt, 33 µF Aluminum Electrolytic Capacitor (AEC)

and a Kemet 500 volt, 2.9 µF MLCC were compared to an EEStor equivalent capacitor estimated

performance, using Phase 8 data for the performance of the dielectric layers. Tables 2 and 3 show the

results of the same comparisons made with Phase 9 data (details in Appendix 3). Phase 8 showed

that capacitors made from EEStor’s Phase 8 dielectrics were significantly smaller per farad at voltage

and temperature than existing capacitors. In all cases EEStor Phase 9 capacitors are less than half

the size of the EEStor Phase 8 for the same performance. As discussed in EEStor’s press release,

EEStor Poised to Disrupt the Multi-Billion Dollar Aluminum Electrolytic Capacitor Market, capacitor

manufacturing costs are based primarily on the amount and cost of raw materials, with ceramic

capacitors having the lowest cost structure for raw materials among AEC, Tantalum or Film capacitors.

Since ceramic capacitors have the lowest material cost and long expected lifetime and EEStor ceramic

capacitors have the smallest volume for a given capacitance at operating conditions, EEStor Phase 9

dielectrics enable capacitors that are significantly cheaper per farad per year than existing technologies.

In addition, EEStor dielectrics will offer enhanced design options due to their decreased volume for the

same capacitance in comparison to current solutions. The drastic increases in Phase 9 dielectric

performance enables much smaller volume capacitors than those based on Phase 8 dielectrics,

enabling even greater commercial advantage to manufacturers using EEStor’s CMBT-Glass

hybrid dielectric as can be seen in table 2.

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Table 2. Size Comparison for KEMET AEC to EEStor Equivalent Capacitors from Phase 8 and

Phase 9

Capacitor Capacitance

(µF)

Voltage (V) Volume (cm3) % smaller than

Kemet

Kemet 33 40 1.57 0

EEStor Phase 8 33.2 40 0.873 44%

EEStor Phase 9 33.1 40 0.416 73%

Table 2. Above shows Phase 8 based 40 volt 33 µF capacitor comparison has a volume of

0.874 cm3, while the Phase 9 version requires only a volume of 0.416 cm3 for the same performance.

The Kemet capacitor is then 80% larger than the EEStor Phase 8 equivalent and is 277% larger than

the Phase 9 equivalent. In addition, along with the increase in κ at field the resistivity of the material

for Phase 9 has increased, resulting in an increased time constant for this Phase 9 material of

1,265 seconds (increased from the 474 seconds of Phase 8). Phase 9 shows the disruptive

potential of the EEStor CMBT-Glass hybrid dielectric has increased because the market advantage of

EEStor’s technology is significantly enhanced over the already formidable advantage demonstrated in

our Phase 8 results.

The DC bias characteristics of Phase 9 samples can be seen in the following graph of the

Polarization to Electric Field (PE) plots in Figure 1. PE plots map the polarization of a dielectric vs the

electrical field for a charge and discharge cycle. For a detailed discussion regarding PE plots see the

Appendix of EEStor’s Phase 7 White Paper. As a reminder, the slope of the PE plot at any point on

the line represents the capacitance of the dielectric at that field (and thus its κ, for a layer of fix

dimension). This means that, if the bottom line of the plot (or the charge curve) has little change in

slope with increasing field, then there is little change in capacitance or κ with increasing field. Figure 1.

contains the PE plots of two samples from Phase 9 testing. Samples 432-6 and 434-6, the first number

denotes the number of the sintered disc of CMBT-glass hybrid material. The second number identifies

the specific slice of that disc. The PE plots shown in Figure 1. Are from 3rd party testing performed by

Radiant Inc. on both the 434 and the 432 CMBT-Glass hybrid dielectrics. They show very low loss and

very low saturation with a near linear response to field.

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Figure 1. PE plots for samples of the phase 9, 434 and 432 dielectrics (Radiant Inc. Phase 9)

This DC bias characteristic is evident in both the nested PE plot loops for sample 434-6 shown

in Figure 2. (and as reported in MRA’s Phase 9 Report, DC bias graphs in Figures 3-6). The following

graph shows a near linear response to field up to 6800 volts or 8.7 V/µm with very little loss, and an

efficiency of greater than 95% for all voltages.

Figure 2. Nested PE plots for sample of the , 434 dielectric at increasing voltage (Radiant Inc.

Phase 9)

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This near linear slope shows that the κ does not drop significantly with field, allowing EEStor’s

volume performance advantage to extend to higher voltage capacitors. Remember that the energy

density (ED) of the sample is given by the triangular area limited by the vertical axis (µC/cm²) crossing

0 on the left, the PE loop at the bottom, and an imaginary horizontal line going from the y axis on the

left to the tip of the PE loop on the right. Higher field and steep straight slope of the PE loop results in

the ED area growing at the square of the increase in field.

Figure 3 Shows the drop-in capacitance for sample 432-6 as tested by Intertek (and as reported

in Intertek Phase 9 report on page 6). From the inset in Figure 3, it can be seen that with a DC bias up

to 1.4 V/µm, the sample is still hold 100% of its capacitance. The capacitance does not drop below

0.4 nF until 4.4 V/µm. At 4.4 V/µm. the κ has dropped to 1255 from 1284 at 0.1 V/µm, a drop of 2.2%,

and by 22.2 V/µm the κ has dropped to 783, (a drop of only 39%). This DC bias performance by

EEStor’s CMBT-Glass hybrid material is a significant differentiator over other existing type II

ceramic dielectrics.

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Figure 3. DC Bias Characteristics of Sample 432-6

The ability to maintain κ at high field allows EEStor CMBT-Glass dielectric to continue to produce

more capacitance at higher voltages per unit volume than other current capacitors. In Table 3, a

2.9 microfarad 500 volt MLCC capacitor from Kemet is compared to an EEStor Phase 8 and phase 9

equivalent. The Kemet ceramic MLCC is 645% larger for the same capacitance as the Phase 8 EEStor

equivalent and 1437% larger than the Phase 9 EEStor equivalent. In addition, the time constant of 542

seconds for the phase 9 dielectric is over double the EEStor Phase 8 value of 208 seconds.

As it was done in Phase 8, we need to adjust this volume for the thermal performance difference

of the two dielectrics. The Phase 9 thermal performance is better than Phase 8, showing less drop of

capacitance with temperature, however, the Kemet MLCC capacitance does not drop as much with

temperature as either of the EEStor dielectrics. The Kemet capacitor features a capacitance change of

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+ 15% to -15% over a temperature range of -55° to +125°C. The EEStor CMBT-Glass capacitor has a

capacitance change of + 40% to - 42%. over the same temperature range. To make up for this loss of

performance with temperature, at this stage of development, the EEStor capacitor will have to be

slightly oversized to provide a temperature equivalent performance comparison. The capacitance for

the EEStor CMBT-Glass hybrid Phase 9 capacitor would need to be increased to 5 microfarads to

ensure 2.9 microfarads at 125°C. An EEStor MLCC with this capacitance would have a volume of 0.28

cm³, so the Kemet MLCC is still 779% larger than EEStor Phase 9 performance equivalent.

Table 3. Size Comparison for KEMET MLCC to EEStor Equivalent Capacitors from Phase 8 and

Phase 9

(Details of Calculations in Appendix 3)

Capacitor Capacitance

(µF)

Voltage (V) Volume (cm3) % smaller than

Kemet

Kemet 2.9 500 2.46 0

EEStor Phase 8 2.9 500 0.33 86%

EEStor Phase 8

(125°C)

6.7 500 0.73 70%

EEStor Phase 9 2.9 500 0.16 93%

EEStor Phase 9

(125°C)

5 500 0.28 88%

In addition to improved voltage saturation with electric field, Phase 9 samples showed significant

improvement in the dielectric’s temperature stability as measured by the Temperature Coefficient of

Capacitance (TCC). Figures 4-7, show thermal and field performance as demonstrated by TCC and

DC Bias measurements made by MRA for CMBT and CMBT-Glass hybrid dielectrics from Phases 7, 8

and 9. These figures show that the TCC and DC bias characteristics can be drastically altered by the

addition of glass to CMBT when formulating EEStor’s dielectrics.

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Figure 4. MRA K square Sample l-3H CMBT Only DC Bias and TCC Plots

Figure 5. MRA phase 7a Sample 344-3 CMBT/Glass Hybrid DC Bias and TCC Plots

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Figure 6. MRA phase 9 Sample 434-1 CMBT/Glass Hybrid DC Bias and TCC Plots

Figure 7. MRA phase 9 Sample 431-4 CMBT/Glass Hybrid DC Bias and TCC Plots

The above plots show that small differences in the types of glass, glass content, coatings

and/or other additions to the powder can make drastic changes to the Thermal Coefficient of

Capacitance and to the DC bias voltage saturation characteristics of CMBT-Glass hybrid

dielectrics.

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EEStor CMBT-Polymer Hybrid Dielectrics

The EEStor’s CMBT-Polymer hybrid dielectrics performances disclosed in Phase 9 show the

improvement over the last CMBT-Polymer (Ultra) dielectric tests, which were conducted in Phase 6 testing.

Performance improvements over Phase 6 CMBT-Polymer dielectrics resulted from two different polymer

improvement paths, named UH and UL.

Table 4 shows the efficiency near break down and the returned energy for both UH and UL

samples from Phase 9 have significantly increased due to reduced leakage compared to Phase 6

Ultra.

Table 4. Phase 6 and Phase 9 efficiency and energy recovered near breakdown

Sample Volts in V/µm Energy Returned in J/cc

(Wh/l)

efficiency near break

down

Phase 6 Ultra 273 0.2856 (0.0793) 3%

Phase 9 UH 148 0.893 (0.248) 71%

Phase 9 UL 152 2.10 (0.58) 77%

Phase 9 UL (EEStor tested App.

A)

243 5.92 (1.64) 79%

These improvements to efficiency can also be seen in the PE plots of the three dielectrics.

Figure 8, shows PE plots for Phase 6 Ultra and Phase 9 UH and UL CMBT-Polymer hybrid. The area

between the charge and discharge curve can be seen to be significantly smaller for the Phase 9

dielectrics than for the Phase 6 dielectric. It can be seen from the plots and Radiant 3rd party test data

on dielectric constant in Table 5, that UL and Ultra have about the same relative permittivity (κ), as

they have nearly equal slopes, while UH has a shallower slope that corresponds to a lower κ. It is

also evident that the slope for all three dielectrics are nearly linear illustrating little change in

capacitance with voltage. While the UH samples shallower slope indicates a lower κ than that of

Phase 6 or UL dielectrics, its smaller area between the charge and discharge curves illustrates the

lower loss of UH over these other samples.

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Figure 8. Polymer dielectric Improvement Phase 6 to Phase 9

Table 5. Phase 6 and Phase 9 Relative Permittivity as Measured by Radiant Inc.

Sample Relative Permittivity (κ)

Phase 6 Ultra 57.4

Phase 9 UL 61

Phase 9 UH 30

Additionally, as can be seen from MRA testing from Phase 6 and Phase 9, CMBT-polymers

UH and UL feature improved thermal performance, as indicated by their Temperature Coefficient of

Capacitance (TCC). Phase 9 UL and UH CMBT-polymers show much less change in capacitance

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over a broader temperature range than Phase 6. The following plots show that Phase 9 CMBT-

polymer dielectrics have good thermal stability meeting Y8R and Y7P thermal requirements.

Figure 9. Phase 6 Polymer TCC Plot

Figure 10. Phase 9 UH and UL Polymers TCC Plots

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These CMBT-Polymer hybrid dielectrics are ideally suited for embedded capacitance

applications. A current leader in the space, 3M, sells an Embedded Capacitor Material (ECM) with a κ

of 22 and a breakdown strength of 118 V/µm. EEStor’s CMBT-polymers feature both significantly

higher κ and much higher breakdown voltages (see tables 4 and 5). Additionally, 3M’s dielectric is

epoxy based. The polymer used in EEStor’s CMBT-polymer is significantly cheaper than epoxy,

presenting another advantage to the EEStor CMBT-Polymer hybrid dielectric.

Radiant Inc. is not a standard 3rd party testing organization but is a manufacturer of testing

equipment. Initially, EEStor contracted with Radiant to test EEStor’s dielectrics in anticipation of EEStor

acquiring it’s own Radiant testing system. EEStor now owns it’s own Radiant testing system and

therefore can measure PE plots. EEStor undertook a validation of its new Radiant testing system by

testing parts returned after Radiant Inc. phase 9 testing. Appendix 2 demonstrates the accuracy of

EEStor’s testing equipment, compared to that used by Radiant Inc. The results indicate extremely good

correlation between systems. Sometimes however, the results differ with time. Figure 11 compares

testing at Radiant Inc. vs that of EEStor for two different UH samples. The Radiant Inc. test at 2500 volts

resulted in a loop that shows more leakage than the 2500-volt loop sample tested right out of production

at EEStor. Additionally, the UH sample tested at EEStor withstood more voltage before breaking down,

as evident by the two larger loops at fields of 3000 and 3900 volts (243 V/µm). These results indicate

in more energy was stored and recovered in these in-house measurements than in the Radiant Inc.

Phase 9 testing

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Figure 11, PE plots of UH samples at EEStor and Radiant at various Fields

Conclusion

This Phase 9 report has detailed the extensive progress EEStor has made in improving

performance of both its CMBT-Glass and CMBT-Polymer hybrid formulations in 2018. Additionally,

Phase 9 points to future enhancement possibilities for each type of dielectric.

Phase 9 CMBT-Glass work has demonstrated that changes in the addition of glass to the

CMBT can drastically change the thermal and DC bias characteristics of the dielectric, roughly

doubling the κ at field it can sustain over the results achieved in Phase 8. The matrix of parameters

that can be adjusted is large and the potential for additional improvements is also expected to be

large.

EEStor’s CMBT-Polymer hybrid dielectric program has shown performance improvements that

are about to start challenging the current Embedded Capacitance Material on the market. Both the

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UL and UH dielectric development programs will be following known paths that EEStor believes hold

the potential for further improvement in breakdown voltage and lower leakage.

For the last year, EEStor has been investigating the marketability of its many dielectrics for

capacitor markets. However, it is still pursuing its ultimate goal of long-term energy storage. As

EEStor has worked to enhance its CMBT dielectrics for commercial applications in the capacitance

space, EEStor has been able to prove several of its EESU fundamentals:

1. CMBT is cubic at room temperature, (proven by XRD, Raman spectroscopy and DSC

measurements)

2. CMBT has a relative permittivity (κ) of over 30,000, (proven by MRA, Intertek and Radiant

testing of sintered CMBT dielectrics)

3. Adding glass to CMBT lowers the sintering temperature, allowing the usage of base metal

electrodes, (proven by a number of CMBT glass dielectrics sintered below 1200°C)

4. Adding glass to CMBT could change its thermal characteristics (Phase 9 graphs 4-7 show the

changes in TCC)

5. Adding glass to CMBT allows its relative permittivity (κ) to stay relatively high as field is

increased. Ultimately EEStor is targeting a κ of greater than 30,000 at low field with a reduced

κ or 18,000 at a field of over 100 V/µm. Phase 9 samples show that glass lowers the κ from

30,000 to a κ in the 1200 to 1500 range and that that κ stays relatively constant up to over

20 V/µm. EEStor has shown that the DC bias characteristics of CMBT can be modified with

glass. It continues to work on further enhancements to its CMBT hybrid dielectrics to achieve

its κ and electric field performance goals.

The path to improving EEStor dielectrics for use in the commercial capacitor space also

advances EEStor along the path to its ultimate EESU energy density goals.

TEST RESULTS

• MRA Phase 9 report C1

• MRA Phase 9 report C2

• MRA Phase 9 report C3

• MRA Phase 9 report C4

• MRA Phase 9 report P1

• MRA Phase 9 report P2

• MRA Phase 9 report P3

• Radiant Phase 9

• Intertek Phase 9

• Understanding EEStor Parameters

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Appendix 1

Radiant tester output of 3900Volt test of UH hybrid dielectric at EEStor Inc.

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Appendix 2

Tests of Sample L3#1095 at Radiant Inc. and EEStor Inc. at various Fields

Below is PE-loops for LE3-1095 obtained in-house and at Radiant Inc. laboratory at three different

voltages. Under cross-validation settings, we barely notice any difference in curves and essentially

reach the same results and conclusions. These results also indicate that we have the capability to

test electrical properties of dielectrics at our test facility with high accuracy and standards.

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Appendix 3

EEStor CMBT-glass dielectric phase 8 and 9 vs. Kemet 40 volt, 33µFarad AEC

A Kemet 40 volt, 33 microfarad aluminum electrolytic capacitor is contained in a cylinder with a

diameter of 10 mm and a length of 20 mm. The cylinder volume is thus: π × 5² × 20 = 1570 mm3 or

1.57 cm3 (https://www.mouser.com/datasheet/2/212/KEM_A4011_PEG124-1104316.pdf)

Phase 8 EEStor CMBT-glass dielectric vs. Kemet 40 volt, 33 µFarad AEC

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Phase 9 EEStor CMBT-glass dielectric vs. Kemet 40 volt, 33 µFarad AEC

EEStor CMBT-glass dielectric phase 8 and 9 vs. Kemet AEC 500 volt, 2.9 µFarad MLCC

Phase 8 EEStor CMBT-glass dielectric vs. Kemet 500 volt, 2.9 µFarad MLCC

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Phase 9 EEStor CMBT-glass dielectric vs. Kemet 500 volt 2.9 µFarad MLCC

Phase 9 EEStor CMBT-glass dielectric vs. Kemet 500 volt, 5 µFarad MLCC

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