14821
However , its energy efficiency is greatly undermined by the large overpotentials of the discharge ( formation of Li ( 2 ) O ( 2 ) ) and charge ( oxidation of Li ( 2 ) O ( 2 ) ) reactions .
 Chemical: Li ( 2 ) O ( 2 ); Chemical: Li ( 2 ) O ( 2 )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Li ( 2 ) O ( 2 ); Chemical: Li ( 2 ) O ( 2 )