Lithium Sulfide (Li2S)/Graphene Oxide Nanospheres with Conformal Carbon Coating as a High-Rate, Long-Life Cathode for Li/S Cells.
In recent years, lithium/sulfur (Li/S) cells have attracted great attention as a candidate for the next generation of rechargeable batteries due to their high theoretical specific energy of 2600 W·h kg(-1), which is much higher than that of Li ion cells (400-600 W·h kg(-1)). However, problems of the S cathode such as highly soluble intermediate species (polysulfides Li2Sn, n = 4-8) and the insulating nature of S cause poor cycle life and low utilization of S, which prevents the practical use of Li/S cells. Here, a high-rate and long-life Li/S cell is proposed, which has a cathode material with a core-shell nanostructure comprising Li2S nanospheres with an embedded graphene oxide (GO) sheet as a core material and a conformal carbon layer as a shell. The conformal carbon coating is easily obtained by a unique CVD coating process using a lab-designed rotating furnace without any repetitive steps. The Li2S/GO@C cathode exhibits a high initial discharge capacity of 650 mA·h g(-1) of Li2S (corresponding to the 942 mA·h g(-1) of S) and very low capacity decay rate of only 0.046% per cycle with a high Coulombic efficiency of up to 99.7% for 1500 cycles when cycled at the 2 C discharge rate.
†Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.|‡Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Yoon
Y
Hwa
†Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.|‡Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Juan
J
Zhao
†Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.|‡Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Elton J
EJ
Cairns
D002244:Carbon / Q000737:chemistry; D011211:Electric Power Supplies; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D018020:Lithium Compounds / Q000737:chemistry*; D054118:Nanospheres / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry*
D018020:Lithium Compounds; D010087:Oxides; D013440:Sulfides; D002244:Carbon; D006108:Graphite; C550775:lithium sulfide
cathodes; energy storage; graphene oxide; lithium batteries; lithium sulfide; sulfur