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Direct Energy, 2018a

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iv<br />

CONTENTS<br />

8 Thermoelectrics 173<br />

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 173<br />

8.2 Thermodynamic Properties . . . . . . . . . . . . . . . . . . 173<br />

8.3 Bulk Modulus and Related Measures . . . . . . . . . . . . . 176<br />

8.4 IdealGas Law . . . . . . . . . . . . . . . . . . . . . . . . . . 178<br />

8.5 First Law of Thermodynamics . . . . . . . . . . . . . . . . 179<br />

8.6 Thermoelectric Eects . . . . . . . . . . . . . . . . . . . . . 180<br />

8.6.1 Three Related Eects . . . . . . . . . . . . . . . . . . 180<br />

8.6.2 Electrical Conductivity . . . . . . . . . . . . . . . . 183<br />

8.6.3 ThermalConductivity . . . . . . . . . . . . . . . . . 184<br />

8.6.4 Figure of Merit . . . . . . . . . . . . . . . . . . . . . 186<br />

8.7 Thermoelectric Eciency . . . . . . . . . . . . . . . . . . . . 188<br />

8.7.1 Carnot Eciency . . . . . . . . . . . . . . . . . . . . 188<br />

8.7.2 Other Factors That Aect Eciency . . . . . . . . . 191<br />

8.8 Applications of Thermoelectrics . . . . . . . . . . . . . . . . 192<br />

8.9 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195<br />

9 Batteries and Fuel Cells 201<br />

9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 201<br />

9.2 Measures of the Ability of Charges to Flow . . . . . . . . . 202<br />

9.2.1 Electrical Conductivity, Fermi <strong>Energy</strong> Level, and <strong>Energy</strong><br />

Gap Revisited . . . . . . . . . . . . . . . . . . . 203<br />

9.2.2 Mulliken Electronegativity . . . . . . . . . . . . . . . 204<br />

9.2.3 ChemicalPotentialand Electronegativity . . . . . . 205<br />

9.2.4 ChemicalHardness . . . . . . . . . . . . . . . . . . . 207<br />

9.2.5 Redox Potential . . . . . . . . . . . . . . . . . . . . 207<br />

9.2.6 pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208<br />

9.3 Charge Flow in Batteries and Fuel Cells . . . . . . . . . . . 211<br />

9.3.1 Battery Components . . . . . . . . . . . . . . . . . . 211<br />

9.3.2 Charge Flow in a Discharging Battery . . . . . . . . 212<br />

9.3.3 Charge Flow in a Charging Battery . . . . . . . . . . 213<br />

9.3.4 Charge Flow in Fuel Cells . . . . . . . . . . . . . . . 214<br />

9.4 Measures of Batteries and Fuel Cells . . . . . . . . . . . . . 216<br />

9.4.1 Cell Voltage, Specic <strong>Energy</strong>, and Related Measures 216<br />

9.4.2 PracticalVoltage and Eciency . . . . . . . . . . . . 219<br />

9.5 Battery Types . . . . . . . . . . . . . . . . . . . . . . . . . . 223<br />

9.5.1 Battery Variety . . . . . . . . . . . . . . . . . . . . . 223<br />

9.5.2 Lead Acid . . . . . . . . . . . . . . . . . . . . . . . . 225<br />

9.5.3 Al kal ine . . . . . . . . . . . . . . . . . . . . . . . . . 226<br />

9.5.4 NickelMetalHydride . . . . . . . . . . . . . . . . . . 227<br />

9.5.5 Lithium . . . . . . . . . . . . . . . . . . . . . . . . . 228

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