Stretchable Carbon Nanotube Dilatometer for In Situ Swelling Detection of Lithium-Ion Batteries

Abstract

Advances in lithium-ion batteries (LIBs) have enabled the realization of lightweight power sources with high energy density, specific capacity, and cyclic stability. As LIBs are inherently subjected to thermomechanical stress during operation, their volume change can be indicative of their electrochemical reactions and safety status. In this study, a carbon nanotube (CNT)-based dilatometer that is stretchable and can be conformally mounted on the surface of LIBs has been developed for sensitive and in situ measurements of the LIB swelling. The CNTs form a percolation network on top of a thin elastomer and exhibit a positive gauge factor of ∼50 and a negative temperature coefficient of resistance of −0.075% K −1 , enabling a quantitative extraction of the extent of swelling. As a result, both regular (∼50 μm swelling by lithiation/delithiation cycles) and irregular (a few millimeter swelling by abnormal gas evolution because of increased temperature) reactions of LIBs are successfully detected in real time. Unlike the conventional dilatometers that are complex, expensive, and bulky, the CNT sensor, because of its simplicity, portability, and sensitivity, is useful for understanding electrochemical reactions and preventing serious failures of portable LIBs, without disassembling them from the other components of the device.

Direct‐Printing of Functional Nanofibers on 3D Surfaces Using Self‐Aligning Nanojet in Near‐Field Electrospinning

“…[ 48,49 ] In this matter, the conductive ground layer is required to enable the NFES process, in which several approaches can be employed. For example, silver nanowires or carbon‐nanotube can be spray‐coated on surfaces [ 49,50 ] and then acts as a ground electrode for the NFES process. In case the deposition of conductive materials should be avoided and the insulating surface should be remained, surface treatments can be a practical approach.…”

Carbon nanotube-graphene hybrids for soft electronics, sensors, and actuators

“…However, conventional physical sensors based on thin films and nanowires exhibit insufficient performance for practical applications, such as by having a narrow sensing range and/or low sensitivity [69][70][71][72]. In recent years, CNTs and graphene have been introduced as sensing materials to fabricate flexible physical sensors with a wide sensing range and high sensitivity [73][74][75][76][77][78][79][80][81][82][83][84]. CNT-based physical sensors have high flexibility but suffer from poor sensitivity.…”

Safer Lithium‐Ion Batteries from the Separator Aspect: Development and Future Perspectives

“…The external protection device can improve the overall safety of the battery system, such as setting a safety valve on the battery case, connecting a series of components for detecting the temperature or volume change, and thermally fusing to prevent the battery from overheating. [ 7 ] In addition, the thermal management system is employed to control the operation temperature of batteries within a safe range to prevent the occurrence of thermal abuse. [ 8 ] Comparatively, developing component materials (e.g., cathode, anode, electrolyte, and separator) with high thermal stability and the intrinsic safety is the ultimate solution to improve the safety of LIBs.…”