Creasable Batteries: Understanding Failure Modes through Dynamic Electrochemical Mechanical Testing Aaron J. Blake Ryan R. Kohlmeyer Lawrence F. Drummy Jacob S. Gutiérrez-Kolar Jennifer Carpena-Núñez Benji Maruyama Reza Shahbazian-Yassar Hong Huang Michael F. Durstock 10.1021/acsami.5b11175.s002 https://acs.figshare.com/articles/media/Creasable_Batteries_Understanding_Failure_Modes_through_Dynamic_Electrochemical_Mechanical_Testing/2091085 Thin-film batteries that can be folded, bent, and even repeatedly creased with minimal or no loss in electrochemical performance have been demonstrated and systematically evaluated using two dynamic mechanical testing approaches for either controlled bending or creasing of flexible devices. The results show that mechanically robust and flexible Li-ion batteries (Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>//LiFePO<sub>4</sub>) based on the use of a nonwoven multiwalled carbon nanotube (MWNT) mat as a current collector (CC) exhibited a 14-fold decrease in voltage fluctuation at a bending strain of 4.2%, as compared to cells using traditional metal foil CCs. More importantly, MWNT-based full-cells exhibited excellent mechanical integrity through 288 crease cycles, whereas the foil full-cell exhibited continuously degraded performance with each fold and catastrophic fracture after only 94 folds. The enhancements due to MWNT CCs can be attributed to excellent interfacial properties as well as high mechanical strength coupled with compliancy, which allow the batteries to easily conform during mechanical abuse. These results quantitatively demonstrate the substantial enhancement offered in both mechanical and electrochemical stability which can be realized with traditional processing approaches when an appropriate choice of a flexible and robust CC is utilized. 2016-01-07 00:00:00 enhancement results show 94 folds batterie Creasable Batteries testing approaches metal foil CCs processing approaches MWNT CCs Li 4Ti voltage fluctuation Failure Modes nonwoven multiwalled carbon nanotube electrochemical performance 288 crease cycles electrochemical stability