Chemical cell and electrolysis

Electrochemical cell converts chemical energy into electrical energy, by using spontaneous chemical reactions that take place at the electrodes.

An electrolytic cell decomposes chemical compounds by means of electrical energy, in a process called electrolysis. Important examples of electrolysis are the decomposition of water into hydrogen and hydroxide.

Electrochemical cell 不需電力卻可產生能量，轉化學能量為電能；

後者 （electolytic cell） 需用電力以達到增加化學能量的目的。