{"id":8583,"date":"2014-01-13T11:00:02","date_gmt":"2014-01-13T18:00:02","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=8583"},"modified":"2014-01-13T11:00:02","modified_gmt":"2014-01-13T18:00:02","slug":"hybrid-batteries-in-hybrid-vehicles","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/hybrid-batteries-in-hybrid-vehicles\/","title":{"rendered":"Hybrid Batteries in Hybrid Vehicles?"},"content":{"rendered":"

Frances White of the Pacific Northwest National Laboratory (PNNL) reports that a new anode quadruples the life of a test lithium-sulfur battery<\/a> and could lead to much lower costs for electric vehicles and large-scale energy storage.<\/p>\n

This blog has noted that many researchers focus on development of better cathodes, or anodes, or electrolytes exclusively, neglecting a more holistic, or whole battery approach to their delving.\u00a0 PNNL scientists have a reason for focusing on anodes, having found that a \u201cbattery with a dissolved cathode can still work.\u201d<\/p>\n

\"PNNL's<\/a>

PNNL’s battery has a hybrid graphite\/lithium anode, unflustered by cathode dissolution<\/p><\/div>\n

What dissolves the electrodes in a battery?\u00a0 \u201cUnwanted side reactions,\u201d according to PNNL, cause the battery\u2019s sulfur-containing cathode to disintegrate slowly and form polysulfide molecules that dissolve into the battery\u2019s electrolyte liquid.\u00a0 This becomes a thin film that forms on the surface of the lithium-containing anode, and grows until the battery will no longer operate.<\/p>\n

Rather than trying to stop sulfur leakage from the cathode as others have, PNNL added a protective graphite shield to the a node.\u00a0 This \u201cthin matrix of connected carbon molecules,\u201d common in lithium battery anodes, keeps the sulfur side reactions away from the anode\u2019s surface and prevents growth of the thin film that eventually stops ion movement to the anode.<\/p>\n

Their anode is unique in being a hybrid combination of graphite from lithium-ion batteries and lithium from conventional lithium-sulfur batteries.\u00a0 PNNL Laboratory Fellow Jun Liu and his research team found this quadrupled longevity for their battery.\u00a0 Normally, lithium-sulfur batteries with conventional anodes stop storing energy after about 100 charge-and-discharge cycles.\u00a0\u00a0 The same batteries with PNNL\u2019s hybrid anode \u201cworked well past 400 cycles\u2026 and tested under the same conditions.\u201d<\/p>\n

Lui reports that even though \u201cSulfur is still dissolved in a lithium-sulfur battery that uses our hybrid anode\u2026tests showed a battery with a hybrid anode can successfully be charged repeatedly at a high rate for more 400 cycles, and with just an 11-percent decrease in the battery’s energy storage capacity.”<\/p>\n

As always in such reports, the authors lay in a few caveats<\/em>, noting that research done with small, thin-film test batteries may not show similar results with versions we might plug into our EVs or energy-storage centers.\u00a0 \u201cLiu noted tests with a larger battery system would better evaluate the performance of PNNL’s new hybrid anode for real-world applications.\u201d<\/p>\n

He added, “Lithium-sulfur batteries could one day help us take electric cars on longer drives and store renewable wind energy more cheaply, but some technical challenges have to be overcome first. \u00a0PNNL’s new anode design is helping bringing us closer to that day.”<\/p>\n

Lui and his team\u2019s paper, \u201cManipulating surface reactions in lithium-sulfur batteries using hybrid anode structures\u201d \u00a0has been published in Nature Communications.<\/em><\/a> \u00a0The team included Cheng Huang, Jie Xiao, Yuyan Shao, Jianming Zheng, Wendy D. Bennett, Dongping Lu, Saraf V. Laxmikant, Mark Engelhard, Liwen Ji, Jiguang Zhang, Xiaolin Li, and Gordon L. Graff.<\/p>\n

Research was supported by the Department of Energy’s\u00a0Office of Science<\/a>\u00a0(BES), with additional support from DOE’s\u00a0Advanced Research Projects Agency-Energy<\/a>, and DOE’s\u00a0Office of Energy Efficiency and Renewable Energy<\/a>.\u00a0 Some of this research was performed at\u00a0EMSL, DOE’s Environmental and Molecular Sciences Laboratory<\/a>\u00a0at PNNL.<\/p>\n