Instantaneous and Repeatable Self-Healing of Fully Metallic Electrodes at Ambient Conditions

Abstract

Recent approaches in self-healable electrodes use polymers with exhibiting significantly low electrical conductivity, compared to conventional metals. Such self-healable electrodes also require external stimuli to initiate self-healing, or present slow restoration for their intrinsic healing. Herein, we introduce an instantaneous and repeatable self-healing of highly conductive, fully metallic electrodes at ambient conditions. These electrodes consist of silver and liquid metal (with no polymer), and exhibit a sufficiently high conductivity of 2 S/μm. The liquid metal (LM) component enables instantaneous and repeatable self-healing of these electrodes (within a few milliseconds) under no external energy as well as high stretchability. Additionally, the inclusion of silver in this LM improves the mechanical strength of this composite, thereby overcoming the limitation of a pristine LM that has low mechanical strength. Moreover, this composite formation can be effective in preventing the penetration of gallium atoms into different metals, while preserving electrical contact properties. Also the self-healable nature of electrodes enables their outstanding sustainability against electrical breakdown at relatively high electric fields. Furthermore, the compatibility of these self-healable electrodes with conventional photolithography and wet etching facilitates high-resolution patterning for device fabrications, as demonstrated in an example with a self-healable organic light-emitting diode display.

Progress and Roadmap for Intelligent Self‐Healing Materials in Autonomous Robotics

“…[67] For example, Park et al showed that they could autonomously selfheal silver-LM at ambient environment. [68] To guide the engineers on the design of the robots based on the strategy, we list a table of low melting point metals that could be incorporated inside the metal matrix for self-healing of metals (Table 1). As an act to protect the environment, toxic lead and cadmium are excluded in the listed alloying elements, although they are not uncommon for low melting alloys.…”

Smart Sensing Systems Using Wearable Optoelectronics

“…[40] In addition to the aforementioned materials, eutectic galliumÀ indium alloy (EGaIn) is a liquid metal suitable for stretchable applications. [41][42][43][44][45] Park et al developed 3D printing technologies of intrinsically stretchable liquid metals, as shown in Figure 1h. [42] In addition, Park et al fabricated self-healing, stretchable materials, consisting of silver and liquid metals.…”

“…[42] In addition, Park et al fabricated self-healing, stretchable materials, consisting of silver and liquid metals. [44] These Ag-liquid metal composites can endure up to 1000 stretching cycles. In addition, although the composites had a failure %70% tensile strain, the composites can self-heal after release.…”

“…In addition to the aforementioned materials, eutectic gallium−indium alloy (EGaIn) is a liquid metal suitable for stretchable applications . Park et al developed 3D printing technologies of intrinsically stretchable liquid metals, as shown in Figure h .…”

“…Park et al developed 3D printing technologies of intrinsically stretchable liquid metals, as shown in Figure h . In addition, Park et al fabricated self‐healing, stretchable materials, consisting of silver and liquid metals . These Ag‐liquid metal composites can endure up to 1000 stretching cycles.…”