William R. Bennett

Glenn Research Center, Cleveland, Ohio

Method for Predicting the Energy Characteristics of 

Li-Ion Cells Designed for High Specific Energy

NASA/TM—2012-217407

August 2012
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William R. Bennett

Glenn Research Center, Cleveland, Ohio

Method for Predicting the Energy Characteristics of 

Li-Ion Cells Designed for High Specific Energy

NASA/TM—2012-217407

August 2012

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
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NASA/TM—2012-217407 1

Method for Predicting the Energy Characteristics of 

Li-Ion Cells Designed for High Specific Energy

William R. Bennett

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio 44135

Abstract

Novel electrode materials with increased specific capacity 

and voltage performance are critical to the NASA goals for 

developing Li-ion batteries with increased specific energy and 

energy density. Although performance metrics of the individual electrodes are critically important, a fundamental understanding of the interactions of electrodes in a full cell is 

essential to achieving the desired performance, and for establishing meaningful goals for electrode performance in the first 

place. This paper presents design considerations for matching 

positive and negative electrodes in a viable design. Methods 

for predicting cell-level performance, based on laboratory data 

for individual electrodes, are presented and discussed.

1.0 Introduction

NASA’s High Efficiency Space Power Systems (HESPS) 

Project is developing advanced lithium-ion cells for future 

NASA exploration missions under the Enabling Technology 

Development and Demonstration (ETDD) Program. This 

work, which began under the Exploration Technology Development Program (ETDP) Energy Storage Project, combines 

the efforts of industrial partners and contractors to develop 

aerospace cell designs with enhanced specific energy and 

safety characteristics (Ref. 1).

A spreadsheet model was developed to predict cell-level 

specific energy under relevant operating conditions, and to 

perform “what-if?” analysis for different cell materials and 

designs. Estimates of the cell discharge voltage profile use 

laboratory data for anodes and cathodes under relevant rates 

and temperatures. Cells are being developed to have a 35 Ah 

capacity when discharged at a C/10 rate to 3 V at 0 °C—in 

alignment with the stated ETDP key performance parameters 

(KPPs). Laboratory data for the individual electrodes in halfcells, collected at 0 °C and C/10 rates, are used to project 

capacity and energy at reduced temperature.

Key assumptions:

• Prismatic cells sized to deliver 35 Ah capacity with discharge to 3 V at 0°C

• Energy/capacity estimated for C/10 discharge rates

• Use electrode specific capacity observed in laboratory 

testing with limited number of cycles (neglects capacity 

loss with cycling)

• Scale electrode area to produce practical loading of active material on the foil current collector substrate

• Positive electrode porosity = 30 percent

• Negative electrode porosity = 35 percent

• Neglect electrode expansion with state of charge

Electrode loading—the quantity of active material per unit 

area of electrode—has a significant impact on cell performance and specific energy. Low loading levels require large 

electrode area and a greater mass of current collector foil. This 

situation is favorable for cells designed for high power applications, but produces a heavy cell with relatively low specific 

energy. High loading levels reduce current collector mass, but 

if the electrode layer becomes too thick, the utilization of 

electrode material at practical rates can be compromised. 

Optimization of loading level requires experimentation, but 

practical loadings are generally around 3 mAh/cm2

. Moshtev 

and Johnson (Ref. 2) presented a physical analysis of commercial lithium-ion cells (c. 1999) which shows electrodeloading levels ranging from 2.4 to 3.4 mAh/cm2

.

Physical cell design assumes a 0.5 mm thick aluminum case 

with 73 electrode pairs. The electrodes consist of alternating 

positive and negative electrode plates. The electrode plates are 

coated on both sides. The choice of the number of electrode 

pairs influences the number of internal tab connections as well 

as the thickness of the finished cell. The weight of case material 

is minimized when the cell shape is a cube. However, this 

geometry produces a thick cell with a large number of internal 

tab connections, and adds complexity to the assembly process.

The choice of 73 pairs was believed to be representative of 

practical commercial prismatic cells. Cell construction is 

illustrated in Figure 1. Electrode tabs are joined together in the 

header space between the electrode top edge and the inside of 

the cover. Height, width and thickness are defined in Figure 1. 

The electrode aspect ratio is assumed to be 1.5 (H/W). This 

choice produces a tall cell with reduced width and helps to 

reduce the volume of the header space at the “top” of the cell. 

Note that the cell in Figure 1 has an electrode aspect ratio that 

is less than one. Heat transfer and current distribution are also 

affected by the choice of aspect ratio. This effort neglected 

these affects.

Mass calculations include allowance for terminals, feedthrough seals and internal tab connections. These are based on 

inspection of practical commercial cells of similar capacity.

The cell mass includes allowance for 30 percent excess
NASA/TM—2012-217407 2

Figure 1.—Prismatic cell construction.

electrolyte, relative to the amount required to exactly fill the 

porous volume of the electrodes and separator material. This 

measure assures that the electrodes and separators are fully 

imbibed with electrolyte during the life of the cell. Negative 

electrodes and separators are assumed to be 2 mm larger than 

the positive electrode (all around) to prevent edge contact and 

short-circuiting inside the cell. The spreadsheet model assumes that the separator film covers the entire face of the 

oversized, negative electrodes. Alternatively, the smaller 

positive electrode may be enclosed in a separator pouch, 

resulting in less separator material.

Calculations use the density of the electrode components 

and the assumed porosity of the electrode layers to compute 

the total volume of electrode material. The assumed electrode 

area, aspect ratio and number of plates establish the dimensions of the electrode package. The cell model computes the 

mass of the case material required to enclose the cell bundle, 

with user-specified clearance at the edges, base and header 

space of the cell. The mass of internal tab connections is

computed to reflect the number of electrode pairs.

Testing of the individual electrodes provides capacity and 

discharge voltage data that is used to forecast cell-level 

combinations. This report discusses the details of the forecasting methods that are used. Sample calculations are presented 

for state-of-the-art graphite and layered cathode material.

2.0 Performance of Single Electrodes in 

Half-Cells

2.1 Testing Considerations

Testing of the single electrodes is performed in half-cells 

with lithium metal counter-electrodes. Voltage limits for 

formation and cycling are based on anticipated maximum 

useable potential windows for the electrode materials under 

study. These potential windows represent the full utilization 

(maximum specific capacity) of the electrode material. Capacity matching, and the choice of P/N ratio, limits the useable 

electrode potential window in full cells. This will be illustrated 

in the example, which follows.

2.2 Typical Electrode Data

Screening of lithium-ion electrodes is usually performed in 

half-cells with lithium metal counter-electrodes having a 

substantial excess capacity relative to the electrode under 

study. The lithium counter-electrode serves as a pseudoreference electrode, providing data for the individual electrode 

voltage versus lithium. Laboratory data for the first three 

cycles of practical, state-of-the-art positive and negative 

electrodes appears in Figure 2.

H

W

T
NASA/TM—2012-217407 3

Figure 2.—The first three charge/discharge cycles of 

a positive and negative electrode in half-cells with 

lithium metal. Electrode potential versus specific 

capacity in mAh per gram of active material. Data 

at room temperature.

Figure 2 presents electrode potential as a function of the cumulative capacity (a running total of the charge capacity minus 

the discharge capacity over several cycles). On charge, the 

positive electrode is delithiated and becomes more positive. At 

the same time, the negative electrode accepts lithium ions on 

charge and becomes more negative. On discharge, the process is 

reversed. For both electrodes, the total first charge capacity is 

noticeably greater than the discharge capacity. The difference 

between cumulative charge and discharge capacity is defined as 

the irreversible capacity of the electrode. The reversible capacity is the capacity that is available to the load after the electrode 

is formed. The total capacity absorbed by the electrode is the 

sum of the reversible and irreversible capacity. 

For the positive electrode in Figure 2, a cumulative total 

capacity of 183 mAh/g is absorbed in the first few cycles. The 

reversible capacity is 153 mAh/g. The irreversible capacity of 

30.1 mAh/g is equivalent to 19.7 percent of the reversible 

capacity.

Similarly, the negative electrode absorbs a cumulative 

charge capacity of 334 mAh/g. The irreversible capacity of 

26 mAh/g is equivalent to 7.7 percent of the reversible capacity. The specific capacity for the Figure 2 electrodes is 

summarized in Table 1.

TABLE 1.—SPECIFIC CAPACITIES 

OF ELECTRODES IN mAh/g

Positive Negative

Irreversible 30.1 25.8

Reversible 152.9 334.5

Total 183.0 360.3

Irreversible (% of rev) 19.7% 7.7%

The reversible specific capacity is used to compute the electrode active material mass that is necessary to meet a desired 

electrode capacity. When performing cell-level calculations 

for capacity-balanced electrodes, the specific capacity 

(mAh/g) is replaced by total capacity (Ah). When expressed as 

a fraction of the reversible capacity, the irreversible capacity

has the same value regardless of the capacity units.

3.0 Capacity Matching

3.1 Reversible Capacity

The reversible capacity represents the stable capacity that is 

delivered by the electrode, after the formation cycles are 

completed. For practical electrodes, the reversible capacity 

stabilizes after several formation cycles and the cumulative 

irreversible capacity reaches a limiting value. This is the 

behavior demonstrated in Figure 2. In poor-performing electrodes, the irreversible capacity may persist in prolonged 

cycling, leading to continued loss of cell capacity and poor 

cycle life. The calculations discussed in this report assume that 

the capacities are stable after formation.

3.2 Irreversible Capacity

Irreversible capacity contributes to the total charge capacity 

that is absorbed by the electrode in the initial (formation) 

cycles. In the case of the positive electrode, the extraction of 

lithium in the first charge induces changes to the crystal 

structure, making it impossible for the same amount of lithium 

to be re-inserted in the subsequent discharge cycle (Ref. 3). In 

this case, the quantity of lithium that is removed cannot be 

replaced. At the negative electrode, the initial transfer of 

lithium reduces the potential and induces electrochemical 

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 100 200 300 400

Neg. Volts vs Li

Cumulative capacity (mAh/g)

25.8 334.5

irr. reversible

discharge

charge

Graphitic negative electrode

10 mV to 1.5 V

2

2.5

3

3.5

4

4.5

0 50 100 150 200

Pos. Volts vs. Li

30.1 152.9

irr. reversible 

charge 

discharge 

Layered positive electrode 

3 to 4.2 V 

Cumulative capacity (mAh/g)
NASA/TM—2012-217407 4

reactions (reduction) with the electrolyte (Ref. 4). The reduction products are electrochemically inactive species that 

comprise the solid electrolyte interphase (SEI). This portion of 

the first charge capacity cannot be accessed in discharge 

because the reduction products are inactive. 

The cell performance forecasts presented in this report assume that the capacity performance for each electrode is the 

same as in half-cells. The irreversible capacity generated by 

each electrode must be absorbed by the opposite electrode, as 

lithium is transferred and current flows during the irreversible 

process. Allowance for the irreversible capacity forms an 

important consideration in the capacity balance of the electrodes in a full cell. 

3.3 Capacity Ratio Considerations

Practical cell design requires that the capacity of the opposing electrodes be “matched”. The electrode pairs have equal 

active area and must exchange the same capacity in cycling.

This is equivalent to completing a material balance for Li in 

the electrodes. The positive electrode represents the source of 

lithium ions for the functioning cell and there must be sufficient negative capacity to absorb the positive capacity (including positive irreversible capacity). The negative electrode is 

assumed to absorb the positive capacity to form the SEI layer 

(satisfying the negative irreversible capacity). The balance of 

remaining positive capacity is assumed to lithiate the negative 

electrode reversibly.

One of the electrodes may be designed with less capacity 

than the other, and will limit the capacity of the cell. In this 

work, calculations assume a positive-to-negative capacity ratio 

(P/N) that is slightly less than one, making the cell positivelimited on charge. This choice is intended to provide a slight 

excess of negative capacity so that lithium can be intercalated 

into the anode host without forming potentially hazardous 

(reactive) metallic lithium. In these calculations, the P/N ratio 

is based on the total capacity of the electrodes (irreversible 

plus reversible capacity).

Sample calculations for a hypothetical, positive-limited,

35 Ah cell are presented below; based on the room temperature electrode performance summarized in Figure 2.

First, assume a positive reversible capacity of 35 Ah. The 

positive irreversible capacity equals 19.7 percent of the 

reversible capacity (19.7 percent × 35 Ah = 6.90 Ah). The 

total positive capacity is equal to 41.90 Ah (= 35 + 6.90).

This calculation uses excess negative capacity with a P/N 

ratio of 0.909 (equivalent to a 10 percent excess negative 

capacity). Note that this is the ratio of total capacities, including irreversible capacity and reversible capacity. For this cell, 

the total negative capacity is 46.09 Ah (= 41.90/0.909).

The negative irreversible capacity is equal to 7.7 percent of 

the reversible capacity. Therefore, the negative reversible 

capacity is 42.79 Ah (= 46.09 Ah/1.077). The irreversible 

capacity is 3.30 Ah (=7.7 percent × 42.79 Ah). Capacity 

elements are summarized in Table 2 and compared side-byside in Figure 3.

TABLE 2.—CAPACITY VALUES 

FOR BASELINE 35 Ah CELL

Capacity in Ah Positive Negative

Irreversible 6.90 3.30

Reversible 35.00 42.79

Total 41.90 46.09

Irreversible (% of rev.) 19.7% 7.7%

Figure 3.—Capacity Balance in a hypothetical 35 Ah cell.

This hypothetical cell has 35 Ah of reversible capacity in 

the positive electrode (solid region in Figure 3). Irreversible 

capacity is 6.90 Ah, illustrated as a hatched region in Figure 3.

This positive electrode will exchange a total capacity of 

41.90 Ah (irreversible + reversible capacity) with the negative 

electrode in order to become fully charged.

Here, the positive reversible capacity limits the useable 

window of operation for the negative electrode to the 35 Ah 

region shown by the arrow in Figure 3. The limited total 

positive capacity prevents the negative from becoming fully 

charged (as expected, since this was the intent of having 

excess negative capacity). In addition, due to the balance of 

irreversible capacities, the negative electrode cannot be 

discharged past the left of the arrow because of the lower limit 

of positive capacity.

Thus, the maximum state-of-charge for the anode is 

90.2 percent:

(6.90 + 35 – 3.30)/42.79 = 90.2%.

The minimum state-of-charge for the anode is 8.4 percent:

(6.90 – 3.30)/42.79 = 8.4%.

The required weight of electrode active material is computed 

using the reversible specific capacity for the electrodes given 

in Table 1 and the total capacity derived in. Results of this 

calculation appear in Table 3.

3.30

6.90

42.79

35.00

0 10 20 30 40 50

Neg

Pos

Capacity (Ah)
NASA/TM—2012-217407 5

TABLE 3.—ELECTRODE ACTIVE

MATERIAL CALCULATION

Positive Negative

Reversible capacity (Ah) 35.00 42.79

Specific capacity (mAh/g) 152.85 334.50

Active material (g) 229.0 127.9

With the mass of electrode materials established, the voltage 

of the electrodes (data from Figure 2) can be determined as a 

function of the common total capacity as shown in Figure 4.

4.0 Discharge Performance Estimation

Here, the process for forecasting cell discharge voltage is 

described. Laboratory data for single electrodes in half-cells,

with lithium metal, is used to predict cell voltage. As seen in 

Figure 4, the positive-limited capacity restricts the useful 

voltage window of the negative electrode. The negative 

electrode in this example will experience the voltage history 

illustrated by the solid black line in Figure 4. The inaccessible 

negative capacity (illustrated by dotted lines) cannot be 

utilized. This comparison illustrates how the irreversible 

capacity and P/N ratio affects the maximum utilization of the 

individual electrodes. The arrow in Figure 4 indicates the 

35 Ah window for cycling capacity. The limits for the negative electrode state-of-charge in cycling were calculated above 

to be between 8.4 and 90.2 percent of the reversible negative 

capacity. 

4.1 First Charge Capacity 

The first charge capacity accounts for the irreversible capacity of both electrodes. Depending on the P/N ratio, only a 

portion of the total electrode capacity of the non-limiting 

electrode can be accessed. The P/N ratio and the balance of 

the irreversible capacity of the electrodes dictate the useful 

state-of-charge window of the electrodes. In most cases, this 

means that the electrodes will not see the full voltage range 

that was used for half-cell testing. This is illustrated for the 

negative electrode in Figure 4. In the initial charge, the total 

capacity of the positive electrode (41.9 Ah) limits the state-ofcharge of the negative to 90.2 percent of its reversible capacity. When the positive electrode is fully discharged, 

8.4 percent of the total negative discharge capacity remains.

Once the state-of-charge window for both electrodes is 

determined (by the material balance described above) the 

discharge voltage for the full cell can be estimated.

4.2 Discharge Capacity at Room Temperature

In this example, the reversible positive electrode capacity is 

fully utilized on discharge, delivering 35 Ah between electrode potential limits of 4.2 to 3 V vs. Li/Li+

. Only a portion of 

the reversible negative capacity is accessed (as discussed 

above) with state-of-charge ranging from 8.4 to 90.2 percent. 

Figure 4.—Electrode voltage profiles in 35 Ah cell.

Figure 5.—Discharge capacity window for the anode.

This 35 Ah portion of negative capacity is illustrated by the 

solid black line in Figure 5: now plotted as discharge capacity. 

The negative electrode has a relatively flat voltage profile in 

this limited window of operation (0.1 to 0.24 V vs. Li/Li+

).

Finally, cell voltage is calculated as the difference between 

electrode potentials (positive minus negative) over the selected 

capacity range. Discharge capacity profiles for the the electrodes and cell appear in Figure 6. For this example, the 

positive electrode capacity was selected to deliver 35 Ah, 

based on a positive electrode cutoff voltage of 3 V vs. Li/Li+

.

Factoring in the effect of the negative electrode, the projected 

cell voltage reaches a 3 V cutoff at only 34.3 Ah, 98 percent of 

the 35 Ah target capacity.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 10 20 30 40 50

Electrode Volts vs. Li

Total capacity (Ah)

positive

negative

3.30

6.90

42.79

35.00

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 10 20 30 40 50

Negative Volts vs Li

Discharge capacity (Ah)

3.6 + 35 = 38.6 Ah

8.4% SOC

6.9 - 3.3 = 3.60 Ah

90.2% SOC
NASA/TM—2012-217407 6

Figure 6.—Electrode and cell potential for the 35 Ah cell.

In practice, the electrode capacity is determined by trialand-error in order to satisfy the goals for cell-level capacity at 

specified cut-off voltages. The spreadsheet model used to 

forecast cell discharge performance automates the calculations 

described above. Analogous calculations can be made for any 

combination of electrodes. For the experimental electrodes 

presented in this report, positive capacity has to be increased 

to 35.75 Ah to achieve 35 Ah at the cell level with a 3 V 

cutoff voltage.

4.3 Electrode Loading and Composition

Electrode loading refers to the mass of electrode material 

per unit electrode area. It is an important parameter in cell 

design. At constant capacity, increased loadings (thicker mix 

layers) offer a reduction in total electrode area and reduce the 

cell mass due to a savings in current collector and separator 

material. There is a trade-off however, since increased loadings tend to diminish the utilization of the electrode material, 

effectively reducing the specific capacity. Electrode loading 

was not dictated in the original list of key performance parameters (KPPs) for electrodes.

In performing cell-level estimates, capacity balance is established as outlined in the sample calculations above. Electrode 

area is then adjusted to produce the desired loading. The 

electrode area in the above example is 12,100 cm2

, with a 

corresponding loading of 2.9 mAh/cm2

. The positive electrode 

mass loading 22 mg/cm2

, including active material and all 

electrode additives. The negative electrode mass loading is 

projected to be 11 mg/cm2

. The electrode layer that is deposited on the current collector foil is estimated to be 80 μm in 

thickness for both electrodes. Electrode composition (binder 

and conductive diluent level) also impact the discharge performance (rate capability) and total electrode mass.

Figure 7.—Projected cell capacity at 0 °C.

4.4 Rate Capability and Temperature Effects

The example calculations above are based on electrode data 

collected at room temperature and C/10 rates. However, the 

ETDP KPP for capacity was originally specified for discharge 

at 0 °C. At reduced temperature (or higher discharge rates); 

the cell voltage reaches the cut-off value at a lower discharge 

capacity. Temperature and rate effects are captured in the 

model by substituting single-electrode data collected under the 

alternative conditions.

Discharge performance for this cell was estimated by 

assuming a 10 percent loss in cathode capacity at 0 °C. The 

reduced positive electrode performance results in a projected 

cell capacity of 31 Ah at the 3 V cutoff (see Figure 7). In order 

to meet the KPP goal of 35 Ah at 0 °C, the hypothetical cell 

discussed here would have to be sized for additional capacity.

4.5 Cell-Level Energy Calculation

Cell discharge energy is calculated by integrating cell discharge voltage over the discharge capacity. This is done 

numerically in the spreadsheet model. This 35 Ah example 

cell delivers 125 Wh at a cell cutoff voltage of 3 V.

Cell mass is calculated with high fidelity by the model and 

includes, all electrode materials, electrolyte, foils, internal 

tabbing connections and terminals. The case material is 

computed to enclose the electrode package with allowance for 

header space and lateral clearance between the inner case wall 

and the edges of the electrodes. The 35 Ah cell presented here 

is estimated to have a mass of 0.72 kg, distributed as shown in 

Table 4.

The projected specific energy for this cell is 174 Wh/kg at 

room temperature. The projected specific energy at 0 °C is 

157 Wh/kg, 90 percent of the room temperature value. 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

0 5 10 15 20 25 30 35

Volts

Discharge capacity (Ah)

positive V vs. Li

negative V vs. Li

cell = positive - negative

34.3 Ah at 3 V 

cell cutoff

3.0

3.2

3.4

3.6

3.8

4.0

4.2

0 5 10 15 20 25 30 35

Cell Voltage (V)

Discharge capacity (Ah)

cell at 23°C

cell at 0°C
NASA/TM—2012-217407 7

TABLE 4.—ESTIMATED CELL

MATERIAL MASS IN GRAMS

Electrochemical 628.3 87.3%

Enclosure materials 48.1 6.7%

Terminals/edge material 2.9 0.4%

Header 40.5 5.6%

Total cell 719.8 grams

Using this model, it is projected that that target capacity of 

35 Ah at 0 °C could be achieved by a cell with a room temperature capacity of approximately 40 Ah. Such a cell would have 

a specific energy of 159 Wh/kg at 0 °C.

5.0 Discussion

The calculation procedures described above provide a 

means for projecting cell-level specific energy based on 

laboratory data for the individual electrodes. These estimates 

capture the effect of irreversible capacity, reversible capacity 

and P/N ratio. Results are based on test data for real electrodes 

in half-cells. The accuracy of such projections depends heavily 

on the assumptions for electrode makeup. In particular, 

changes in porosity and electrode loading will have a significant effect on the rate capability of the electrode. In performing estimates, data at specific loadings and electrode porosity 

was available. 

It has already been pointed out that the capacity balance will 

restrict the allowable capacity window of the electrode with 

excess capacity (the negative electrode in the examples 

above). In turn, the model assumes that the electrode voltage/capacity behavior of the affected electrode is the same as 

if the electrode was fully formed. The portability of the halfcell data, with full state-of-charge, to the model with partial 

formation and state of charge represents a large assumption in 

this work and should be verified experimentally. 

It should be underscored that these estimates represent the 

initial capacity and energy of the cell. Deterioration of performance with cycle life is not captured in these estimates.

The half-cells used to collect data for the single electrodes 

includes ohmic drop for one layer of separator material.

Forecasts for cell voltage are derived by difference between 

the electrode potentials and as such, it includes the ohmic loss 

of two separators. This small error has been neglected in 

making cell-level estimates. 

References

1. C. Mercer et al., “Energy Storage Technology Development for Space Exploration,” NASA/TM—2011-216964

2. R. Moshtev, B. Johnson, Journal of Power Sources 91 

(2000) 86–91

3. A. Manthiram, J. Choi, W. Choi, “Factors Limiting the 

Electrochemical Performance of Oxide Cathodes,” Solid 

State Ionics 177 (2006) 2629–2634

4. S. Flandrois, B. Simon, “Review - Carbon materials for 

lithium-ion rechargeable batteries,” Carbon 37 (1999) 

165–180
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This publication is available from the NASA Center for AeroSpace Information, 443-757-5802

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14. ABSTRACT

Novel electrode materials with increased specific capacity and voltage performance are critical to the NASA goals for developing Li-ion 

batteries with increased specific energy and energy density. Although performance metrics of the individual electrodes are critically 

important, a fundamental understanding of the interactions of electrodes in a full cell is essential to achieving the desired performance, and 

for establishing meaningful goals for electrode performance in the first place. This paper presents design considerations for matching 

positive and negative electrodes in a viable design. Methods for predicting cell-level performance, based on laboratory data for individual 

electrodes, are presented and discussed. 

15. SUBJECT TERMS

Lithium batteries; Storage batteries; Electric batteries; Electrochemical cells; Energy storage; Space mission; Spacecraft power 

supplies; Electric power supplies 

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