New generation of lithiumion batteries could hold more charge—without catching fire

first_img Sign up for our daily newsletter Get more great content like this delivered right to you! Country Shawn L. Minter/AP A Samsung Galaxy Note 7 after its lithium-ion battery caught fire In recent years, researchers have experimented with replacing these organic electrolytes with solid electrolytes or water-based versions that can’t catch fire. But if the operating voltage of these water-based batteries exceeds 1.23 volts (V)—below that of even a 1.5-V AA battery—electrode materials can react with water molecules, splitting them into hydrogen and oxygen gases, often with explosive results. Yet when researchers stay below the 1.23-V threshold, they end up with batteries that store far less energy than traditional lithium-ion cells, which operate at about 4 V.Hope for an alternative arose in 2015, when researchers led by Chunsheng Wang, a materials scientist at the University of Maryland in College Park, reported they created a novel salt-rich water-based electrolyte. This water-in-salt electrolyte (WiSE) promotes the formation a protective solid shield around the electrodes that prevented them from ripping apart water molecules in the electrolyte’s interior. But the electrode materials in those batteries could only muster 3 V.Prospects brightened in 2017, when Wang and colleagues reported they had come up with a positively charged electrode, or anode, material that was compatible with 4-V operation and worked with the WiSE. That just left them to address the negatively charged electrode, or cathode.Now, Wang and his colleagues have done just that. They report today in Nature that they’ve come up with a graphite-based cathode that works with the WiSE at 4 V and above. The new electrode material includes bromine and chlorine, and it ends up protected from the water-based electrolyte by locking reactive electrode materials in solid salt particles around the electrode. The battery starts with lithium bound up in solid lithium-bromine and lithium-chloride salt particles surrounding a graphite electrode made up of layers of carbon atoms. When the battery charges, bromine and chlorine atoms ditch their lithium partners, give up electrons to the cathode, and wedge themselves between graphite’s carbon layers, forming another nice tight solid. The voltage difference between the two electrodes then drives the positively charged lithium ions through the water-based electrolyte to the anode, where they meet up with electrons provided by an external circuit.When the battery discharges during use, the lithium ions give up those electrons and reverse course to the cathode. The electrons travel back through the external circuit to the cathode, where bromine and chlorine atoms grab them and end up with a negative charge. This charge causes them to diffuse back out of the graphite. The lithium ions then snag them, reforming the solid salt particles that stay put until the next round of charging.Wang and his colleagues note that gram for gram, their cathode materials already have about 30% greater charge storage capacity than conventional cathode materials. But it remains to be seen whether the full batteries, including the new electrolyte, will end up holding more energy than commercial versions.Even if they don’t, the new WiSE batteries would not require cobalt, a toxic metal in conventional lithium-ion cathodes. Cobalt mining has been tied to widespread deaths of miners—often children—in the Democratic Republic of the Congo, where the rare metal is relatively abundant. That would make the batteries safer for not only consumers, but miners and the environment as well. By Robert F. ServiceMay. 8, 2019 , 2:10 PM New generation of lithium-ion batteries could hold more charge—without catching firecenter_img Email Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Lithium-ion batteries power everything from laptops to lawn mowers. But they can ignite when damaged because they rely on flammable components. Now, researchers report they’ve redesigned these batteries to work with nonflammable materials. As a bonus, the new batteries might even store more power than current models.The work is “absolutely remarkable progress,” says Gleb Yushin, a materials scientist at the Georgia Institute of Technology in Atlanta, who was not involved with the research. If commercialized, the new batteries could help keep drivers of electric vehicles safe even if they wind up in an accident.Lithium-ion batteries contain three main components: two charge-storing electrodes and a liquid organic electrolyte that separate them. The electrolyte ferries lithium ions back and forth between the electrodes during charging and discharging, but they’re flammable. Click to view the privacy policy. Required fields are indicated by an asterisk (*)last_img

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