Electrochemistry is the study of the interchange between chemical change and electrical work. Electrochemical cells utilize redox reactions to produce or use electrical energy. Redox reactions involve the transfer of electrons between oxidizing and reducing agents. Voltaic or galvanic cells generate electrical energy from a spontaneous redox reaction, while electrolytic cells use an applied electrical current to drive a nonspontaneous reaction. Common components of cells include electrodes, electrolytes, and salt bridges. Oxidation occurs at the anode and reduction at the cathode. Batteries contain multiple connected galvanic cells and electrolysis uses a current to force a nonspontaneous redox reaction.