Possibility of pressure-charged lithium-ion batteries suggested
| Observation of changes in electrode lithium within the electrolyte and elucidation of its behavior
Expected application of pressure-to-electricity conversion energy harvesting

As the demand for large-capacity energy storage media increases, interest in the development of high-capacity lithium alloy batteries is growing.

However, high-capacity lithium alloy batteries have a problem in that their capacity drops drastically and their volume changes significantly due to the pressure generated during the charging and discharging processes. In particular, since the phenomena occurring when pressure is applied to lithium battery electrodes take place at the nanoscale, direct measurement and observation were difficult due to the challenges in establishing the experimental environment.

Dr. Sangtae Kim's team at the Electronic Materials Research Group of the Korea Institute of Science and Technology (KIST), in collaboration with Professor Jongmin Yuk's team at KAIST, revealed the effect of pressure on the battery charging and discharging process and, based on this, presented the possibility of a lithium-ion battery that can be charged by applying pressure on August 30.

The joint research team utilized tin to directly observe and interpret the effects of pressure on batteries at the nanoscale.

Using real-time graphene liquid-phase transmission electron microscopy, the joint research team confirmed the effect of surface pressure on tin nanoparticles and succeeded in directly observing the pressure-induced discharge phenomenon during electrode charging for the first time. Furthermore, through thermodynamic calculations and modeling, they predicted the pressure difference within the battery electrode and interpreted that the resulting electrochemical energy difference serves as the driving force for lithium ion movement and discharge.

Through this study, the research team revealed that pressure and the amount of lithium ions in the electrode have an inverse relationship. Based on this, the possibility was presented to construct a battery that charges by moving lithium through pressure applied by human footsteps or similar movements.

The joint research team developed and tested a battery element that charges when external force is applied, such as by bending or stepping on it, and found that about 0.5 mA of power is generated when one adult male steps on it. This is the power capable of driving a sensor (about 2 mA) with a low-power Bluetooth module attached, assuming that 4 adults step on it.

This device, which generates and stores electricity on its own without an external power supply, is expected to be used in the future for energy harvesting, such as by installing it in paving blocks to convert wasted energy into electricity.

Dr. Kim Sang-tae of KIST stated, “This research result is an achievement in storing mechanical energy as electrochemical energy,” adding, “It is expected to contribute to the design of high-efficiency energy harvesters, such as IoT sensors.”

"Recently, there has been high interest in high-capacity lithium battery materials that can be used stably and for a long time, such as in electric vehicles and energy storage devices," said Professor Yuk Jong-min of KAIST. "This research achievement will be helpful in designing new high-capacity alloy-based electrodes."