Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. Which material has a higher percentage of lithium? 2. Does this help to expla

ID: 932719 • Letter: 1

Question

1. Which material has a higher percentage of lithium?

2. Does this help to explain why batteries made with LiMn2O4 cathodes deliver less power on discharging?

Match the words in the column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete.

LiCoO2

less

LiMn2O4

anode

doesn't explain

Li+

graphite

more

definitely explains

O2

cathode

1. _________ has almost twice as great a mass percent Li as ________.

2. This __________ why LiMn2O4 cathodes deliver less power on discharging. A Li-ion battery produces power by the migration of __________ , but not all the_________ in the_________ material migrates during a full charge. The greater percentage of Li in the_________ material, the more _________ that migrates and the ________ power can be produced upon discharge.

LiCoO2

less

LiMn2O4

anode

doesn't explain

Li+

graphite

more

definitely explains

O2

cathode

1. _________ has almost twice as great a mass percent Li as ________.

2. This __________ why LiMn2O4 cathodes deliver less power on discharging. A Li-ion battery produces power by the migration of __________ , but not all the_________ in the_________ material migrates during a full charge. The greater percentage of Li in the_________ material, the more _________ that migrates and the ________ power can be produced upon discharge.

Explanation / Answer

1. Which material has a higher percentage of lithium?

LiCoO2; LiMn2O4

First, find MW of each

LiCoO2; 97.87

LiMn2O4 180.813

Since there is 1 mol of Li in each sample, then, the lower mass sample will have higher % of Lithium

Q2. Does this help to explain why batteries made with LiMn2O4 cathodes deliver less power on discharging?

2. This definetively explains why LiMn2O4 cathodes deliver less power on discharging. A Li-ion battery produces power by the migration of LI+, but not all the Li+ in the cathode material migrates during a full charge. The greater percentage of Li in the cathode material, the more Li+ that migrates and the more power can be produced upon discharge.