Scientists hope to improve the performance of lithium batteries today by replacing some liquid components with solids,media reported. These experimental devices, known as solid-state batteries, greatly extend the life of electric vehicles and mobile devices by significantly increasing the energy density inside the battery. Now scientists from the Massachusetts Institute of Technology (MIT) are making an exciting future, showcasing a new solid-state battery structure that overcomes some of the current design constraints.
In ordinary lithium batteries, liquid electrolytes move back and forth between positive and negative poles in the form of ions when the battery is charged and discharged, but one of the problems is that the liquid is highly volatile and sometimes even causes a battery to catch fire, as it did on samsung Galaxy Note 7 smartphones.
Replacing this liquid electrolyte with a solid material not only makes the battery safer and less likely to catch fire, but also uncovers new possibilities for other critical components of the battery. According to a recent research paper published in Trends in Chemistry, the anodes of lithium batteries are currently made from a mixture of copper and graphite, but if they are made of pure lithium, it could break the current energy density bottleneck in lithium-ion chemistry.
Therefore, the great potential of pure lithium anodes makes it a high priority for battery researchers, and a key stepping stone is the introduction of a viable solid electrolyte to enable it to work. But there are significant obstacles to achieving this, and when the battery is charged, the accumulation of atoms inside the lithium metal causes it to expand, which in turn causes the metal to contract as a result of a decrease in use, making it almost impossible to continuously contact materials and can also lead to electrolyte rupture.
This is the problem that MIT’s new battery architecture may overcome. The team developed a solid material combination called a mixed ion-electronic conductor (MIEC) and an electron and lithium-ion insulator (ELI). They are made into a three-dimensional honeycomb structure, and nanotubes made from MIEC form a key part of the puzzle.
These tubes are injected into the solid lithium metal to form the battery anode. Since there is extra space inside each tube, lithium metal has excess space to expand and contract when charging and discharging. In this way, the material maintains a delicate balance between solid and liquid materials and moves much like a liquid.
All of this occurs in the cellular anode, where the ELI is coated on the tube wall as an adhesive between it and the solid electrolyte. This means that when the battery is charged, the volatile size of the lithium metal is completely contained inside the structure, while its external dimensions remain the same.
The team’s findings were that the chemical and mechanical properties of the battery’s positive sepsis were stable during charge and discharge, and that lithium did not lose electrical contact with solid electrolytes. In response, the team sees this as a major advance in other experimental solid-state batteries, which typically need to mix a liquid electrolyte to work.
It is reported that the team carried out experiments on the solid-state battery structure, according to the report learned that the battery can withstand 100 charge and discharge cycles, in the process did not show any signs of fracture. In the future, this technology will likely produce anodes that weigh about a quarter of the current design but have the same storage capacity. By combining with other advanced cathode designs, the team says, the future will be able to produce smartphones that are the same weight and size as they are today but only need to be recharged once every three days.