A batch of lithium-ion coin cells are being tested. |Photo source: UCL School of Mathematics and Physical Sciences
Scientists reported science The key to repairing solid-state battery (SSB) failures may be the well-documented mechanical laws that pave the way for longer operational life.
The battery consists of an electrolyte sandwiched between the positive and negative anode. “In most batteries, including lithium-ion batteries in mobile phones, the electrolyte is a liquid solution that is very similar to the salt in water, allowing ions to move back and forth from the electrodes,” Bengaluru, associate professor at the Indian Academy of Sciences in Bengaluru, is not involved in the new study. His team is one of the top groups in India for developing SSBs.
In the battery, ions move freely through the electrolyte, while electrons flow from the cathode to the anode through an external circuit, charging the battery. In the reverse process, the electrons given by the lithium (Li) anode travel to the cathode through an external circuit, supplying power to it. In the battery, the cathode is stabbed through the electrolyte to the corresponding lithium ions during discharge.
“Furry Roots”
In SSB lithium-ion batteries, the ceramic block is an electrolyte. Solid electrolytes last longer and can store more energy, neither volatile nor flammable. Their solid structure separates the two electrodes well, reducing the need for bulky safety equipment and weight. Currently, pacemakers and smartwatches use SSB.
On the other hand, the solid may rupture, so the solid electrolyte is not sothos-saving for volume changes or higher pressures. This leads to a persistent problem called dendritic growth. Li ions fly to the anode and deposit there when charged, forming lithium wires at the anode.
“Have you seen hairy roots growing from the central roots? This happens in plants to maximize their ability to receive nutrients,” Aetukuri said. Like plant roots, the anode tries to absorb as many ions as possible. “Li’s dendritic growth in SSB maximizes the ability of the anode to receive the most Li ions.” But, just as the roots penetrate the rock, the dendrites pierce the electrolyte layer and reach the cathode, creating a short circuit.
Operating microscope
Scientists don’t know the actual physical mechanism that causes this failure. Now, researchers at Shanghai Tangji University and other institutions say the answer may lie in known mechanical problems.
Metal materials experience fatigue due to cyclic loading and unloading. Fatigue cracks and cracks Account for more than 80% Project failed. Researchers speculate that as metal, the LI anode in a battery may suffer similar damage due to multiple charge release cycles.
“Dendrites are microscopic features, which means you need a microscope to visualize them. You need to look at them as they grow – that’s when the cells are running,” Aetukuri said. To do this, scientists use a technique called Operando scanning electron microscopy: “A special microscopy technology in which electrons are light that allows you to see what is happening in small dimensions.”
The researchers observed the anode-electrolyte interface under the microscope and monitored its evolution when it was charged and discharged from coin cells. The cells were initially stable, but after 30 minutes, the microscopic voids burst, expanding and snowballing each other. The electrolyte is eventually captured in the 145th cycle and the battery is short-circuited in the 145th cycle, even if the amount of current is only one tenth of the maximum value the cell can tolerate.
Bend back and forth
“Applying a small current in one direction may not cause failure, but repeated cycles of charging and emissions can create structural defects such as cracks, slip bands and voids,” Comment Published with the paper. When the battery undergoes a charge isolation period, LI is peeled off before plating it back onto it, stripping it from the anode, changing the force applied on the anode.
“You can use a cutter tangent in a GO. … If there is no cutter, you can bend the wire back and forth multiple times and the wire breaks after a few times due to fatigue,” Aetukuri said. “This work shows that riding a bicycle at a low rate is equivalent to applying low stress multiple times, which can also lead to cell failure.”
“While manufacturing may not change much, the battery model predicting SSB failure will be more complex and possibly more accurate due to this work,” Aetukuri said. Future studies should examine how the stress-strain relationship of LI varies with cycle rate and temperature, the researchers wrote.
Unnati Ashar is a free science journalist.
publishing – May 18, 2025 at 06:00 am
