14819
A low - overpotential potassium - oxygen battery based on potassium superoxide .
 Chemical: potassium; Chemical: oxygen; Chemical: potassium superoxide
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: potassium; Chemical: oxygen; Chemical: potassium superoxide