VOLTAIC CELL ELECTROLYTIC CELL Energy is released from Energy is absorbed to drive spontaneous redox reaction nonspontaneous redox reaction System does work on Surroundings (power supply) surroundings do work on system(cell) Surroundings Power Anode (Load) Cathode Anode supply Cathode (oxidation) (reduction) (oxidation) (reduction) Energy Energy () Electrolyte Electrolyte X+ Electrolyte Y with A and B+ Oxidation half-reaction Oxidation half-reaction Ⅹ—-X++e A A+e Reduction half-reaction Reduction half-reaction e-+Y+→Y e" +B+ B Overall (cell)reaction Overall (cell)reaction x+y X++Y;△G<0 A-+B+→A+B△G>0