{"id":10852,"date":"2016-05-03T18:07:10","date_gmt":"2016-05-04T01:07:10","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=10852"},"modified":"2016-05-03T18:07:10","modified_gmt":"2016-05-04T01:07:10","slug":"behang-university-makes-a-better-battery","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/behang-university-makes-a-better-battery\/","title":{"rendered":"Behang University Makes a Better Battery"},"content":{"rendered":"

Lithium-sulfur batteries display winning qualities, such as low production cost, environmental friendliness, and high energy density.\u00a0 Researchers usually give up, or look elsewhere, when the materials\u2019 poor cycle life and loss of active materials on both anode and cathode show up.<\/p>\n

Researchers at Beihang University in Beijing report developing \u201ca new Li-sulfur battery using honeycomb-like sulfur copolymer<\/a> uniformly distributed onto 3D graphene (3D cpS-G) networks for a cathode material and a 3D lithiated Si-G network as anode.\u201d\u00a0 They report \u201ca high reversible capacity of 620 milli-Amp hours per gram, [and an] ultrahigh energy density of 1,147 Watt-hours per kilogram (based on the total mass of cathode and anode), good high-rate capability and excellent cycle performance over 500 cycles (0.028% capacity loss per cycle).\u201d<\/p>\n

\"Structure

Structure and performance of Beihang battery<\/p><\/div>\n

The materials used in the cathode and anode presented challenges.\u00a0 The \u201cinherent insulation of sulfur\u201d on the cathode and the high solubility of polysulfide intermediates cause an inability of the active materials to respond to one another, and the conversion of sulfur into less reactive materials lowers output and cycle life.<\/p>\n

Researchers tried a series of logical steps, including embedding sulfur into activated carbons, and into carbons with pores of varying sizes \u2013 everything from macroporous, mesoporous, and smallest of all \u2013 microporous carbon structures.\u00a0 This improved electric conductivity and slowed loss of active materials, but still limited the amount of sulfur and polysulfides that could be carried on the cathode materials.<\/p>\n

Coating the cathode with sulfur copolymer \u201chas shown good inhibition of polysulfide dissolution, but needs improved electric conductivity.\u201d\u00a0 So, all solutions bring with them an accompanying problem, even with a net gain in output.<\/p>\n

Anodes have another set of initial issues, because the lithium metal reacts with many electrolytes and forms dendrites during charge-discharge cycles, shortening the battery\u2019s life and causing severe safety issues.\u00a0 Alloy-type anodes with similar voltage plateaus to lithium include silicon nanowire and lithiated Si\/SiOx<\/sub>\u00a0nanospheres.<\/p>\n

Perhaps because of the many ways in which lithium and silicon can be combined with graphene and myriad other materials and electrolytes, the authors of the paper on this research conclude this way:<\/p>\n

\u201cThus, a new type of silicon-sulfur battery built from silicon-based anode and sulfur-based cathode is becoming one of next-generation Li-S batteries to overcome their severe cyclability and safety problems. However, the researches of emerging silicon-sulfur battery including the configurations, design and fabrication of appropriate and mutual matching anodes and cathodes are still in the infancy.\u201d<\/em><\/p>\n

Bin Li, Songmei Li, Jingjing Xu and Shubin Yang published their findings<\/a> in the Royal Society of Chemistry\u2019s (RSC\u2019s) journal\u00a0Energy & Environmental Science, <\/em>under the title \u201cA new configured lithiated silicon-sulfur battery built on 3D graphene with superior electrochemical performances.\u201d<\/p>\n