Janus CoMOF‐SEBS Membrane for Bifunctional Dielectric Layer in Triboelectric Nanogenerators

Abstract Considerable research has been conducted on the application of functional nano‐fillers to enhance the power generation capabilities of triboelectric nanogenerators (TENGs). However, these additives often exhibit a decrease in output power at higher concentration. Here, a Janus cobalt metal–organic framework‐SEBS (JCMS) membrane is reported as a dual‐purpose dielectric layer capable of efficiently capturing and blocking charges for high‐performance TENGs. The JCMS is produced asymmetrically through gravitational sedimentation, employing spherical CoMOFs within a diluted SEBS solution. Beyond its dual dielectric characteristics, the JCMS showcases exceptional mechanical durability, displaying notable stretchability of up to 475% and remarkable resilience when subjected to diverse mechanical pressures. Consequently, the JCMS‐TENG produces a maximum peak‐to‐peak voltage of 936 V, a current of 42.8 µA, and a power density of 10.89 W m− 2 when exposed to an external force of 10 N at a 5 Hz frequency. This investigation highlights the potential of JCMS‐TENGs with unique structures, known for their exceptional energy harvesting capabilities, mechanical strength, and flexibility. Additionally, the promising prospects of easily produced asymmetric structures is emphasized with bifunctionalities for developing efficient and flexible MOFs‐based TENGs. These advancements are well‐suited for self‐powered wearables, rehabilitation devices, and energy harvesters.


Figure S1 .
Figure S1.Schematic illustration of the preparation process for CoMOFs/SEBS suspension.

Figure S6 .
Figure S6.Cross-sectional SEM images of JCMSs at different mass ratios.a-d) The quantity of SEBS was fixed, and the amount of CoMOFs was adjusted (9.1 wt% to 37.5 wt%).The

Figure S7 .
Figure S7.The output performance of JCMS-TENG with different mass ratio.(a) Output voltage, (b) current, and (c) charge.

Figure S8 .
Figure S8.Surface potential change of JCMS depending on the mass ratio.

Figure S9 .
Figure S9.Surface SEM images of the dense area of CoMOFs at each mass ratio.

Figure S10 .
Figure S10.AFM images and Rq values of the dense area of CoMOFs at each mass ratio.

Figure S11 .
Figure S11.Normalized surface potential decay of JCMS over time.

Figure S13 .
Figure S13.Output performance of JCMS TENG with the change in relative humidity.

Figure S14 .
Figure S14.The output performance of optimized JCMS-TENG under various external forces.(a) Output current, (b) voltage, and (c) charge.

Figure S15 .
Figure S15.The output performance of optimized JCMS-TENG at various frequencies.(a) Output voltage, (b) current, and (c) charge.

Figure S17 .
Figure S17.SEM image of wJCMS with AgNWs using an ethanol-based solution.The fabrication process is identical to the sample preparation method that utilizes the surface dissolution effect.

Figure S19 .
Figure S19.SEM images demonstrating change of surface morphology on CoMOFs dense layer side of wJCMS resulted by 100% pre-strain of JCMS.

Figure S20 .
Figure S20.Change in output voltage before and after stretching the JCMS at 100% strain.The identical sample was temporarily attached to a 1cm x 1cm acrylic plate and driven by contact-separation at a force of 10 N and a frequency of 5 Hz.

Figure S21 .
Figure S21.Long-term cycle test of wJCMS.The JCMS was attached to a 3cm x 3cm acrylic plate and driven by contact-separation at a force of 10 N and a frequency of 5 Hz.

Figure S22 .
Figure S22.The output voltage of the self-powered finger rehabilitation sensor during fast finger movement.

Figure S23 .
Figure S23.The charging process for different capacitors.A corresponding circuit diagram is provided in the inset.wJCMSs-TENG were driven by a contact-separation under a force of 10 N and at a frequency of 5 Hz.

Figure S24 .
Figure S24.Digital photography driving over 160 LEDs.wJCMSs-TENG were driven by a contact-separation under a force of 10 N and at a frequency of 5 Hz.

Figure S25 .
Figure S25.Experimental set-up for examining the TENG performances.All experiments were driven by a contact-separation with a force of 10 N and a frequency of 5 Hz, unless otherwise noted.

Figure S26 .
Figure S26.Schematic diagram of the circuit for measuring instantaneous power density.

Table S1 .
Advantageous features of JCMS TENG over other TENGs based on Janus structures.

Table S2 .
The quantity of SEBS and CoMOFs used in each mass ratio of JCMS.

Table S3 .
Mechanical properties of JCMS according to each mass ratio.

Table S4 .
Comparison of prior studies on TENGs based on flexible or stretchable materials as self-powered sensors.
*Angle detection is available.**Reversible sensing of angular change