VOA慢速英语:研究人员寻求用钠来制造更好的电池

battery – n. object that provides and stores electricity for things

density – n. the relationship between the weight of a substance and its size

abundant – adj. existing in large quantities

cheap – adj. not costing a lot of money

solar – n. relating to or involving the sun

kilowatt – n. a unit for measuring electrical power

roof – n. the top or covering of something

ion – n. an atom or atomic group that carries an electric charge