China energy storage net news: the army research laboratory at the university of Maryland and the United States for the first time researchers have developed a use of water and salt solution as electrolyte of lithium ion battery, to household electronic devices (such as a laptop) the required standard of 4.0 volts, and not with some commercially available non-aqueous lithium ion battery related to fire and explosion danger.Their work appeared on September 6 in joule.
"In the past, if you want to high energy, you can choose a kind of hydroelectric power lithium ion battery, but you have to compromise in terms of safety, safety if you like, you can use the nimh/metal hydride battery, water but you have to settle for a lower energy."Associate senior author kang xu said that researchers at the U.S. army research laboratory specialize in electrochemistry and material science."Now, we are showing that you can have both high energy consumption and high security."
Study is after the 2015 study of scientific research, produced a similar 3.0 v electrolyte electrolyte, but through the so-called "cathode challenge" to prevent the higher voltage, of which one end of the battery is made from graphite or lithium metal, degradation by aqueous electrolyte.In order to solve this problem, from the volts, leap to, assistant research scientist at the university of Maryland Yang Yangyang first author designed a can be applied to graphite or new type gel polymer electrolyte of lithium anode coating.
The hydrophobic coating from near the surface of the electrode discharge water molecules, and then the charge for the first time, decomposition and form stable anode with liquid electrolyte and solid separation of breakdown products of thin mixture.The water by the battery caused by phase spacing protection layer which is formed in the anode from side effects of the weak, allowing the battery anode materials for use, such as graphite or lithium metal, and better ability of energy density and cycle.
Joint senior author professor wang said: "here is the key to innovation is to create the water to prevent contact with the anode, the water does not break down, also can form the correct interface, to support the high performance battery."Chemical and biological molecular engineering at the university of Maryland at a.j. Ames Clark engineering school.
Compared with the standard of aqueous lithium ion battery, adding gel coating also can improve the safety of the new battery advantage, and compared with any other proposed water-soluble lithium ion battery, improve the energy density.All hydrated lithium-ion batteries benefit from the flammability of water-based electrolytes, and highly flammable organic solvents used in water-based electrolytes.Unique is, however, even if the interphase layer damage (for example, if the battery shell pierced), it will also be with lithium or lithium fossil graphite anode reaction is slow, so as to prevent other cases of smoke, fire or explosion if the damage to the battery to make metal direct contact with the electrolyte
While the power and energy density of new batteries can be applied to commercial applications that are currently used by more dangerous non-water battery services, some improvements will make it more competitive.In particular, the researchers hope to increase the total number of performance cycles the battery can complete and reduce the cost of materials as much as possible."Now we're talking about 50-100 cycles, but compared to organic electrolyte batteries, we want to reach more than 500," Mr. Wang said.
The researchers also noted that electrochemical operations after jumping to four volts were also important outside of battery technology."This is the first time we have been able to stabilize a real reactive anode in a water-based medium, such as graphite and lithium," Mr. Xu said.This opens up many different topics in the field of electrochemical window, including sodium ion batteries, lithium sulfur batteries, involving a variety of zinc and magnesium ion chemicals, electroplating and even electrochemical synthesis;We haven't fully explored them yet.