Regulating Thermogalvanic Effect and Mechanical Robustness via Redox Ions for Flexible Quasi‑Solid‑State Thermocells

The design of power supply systems for wearable applications requires both flexibility and durability.Thermoelectrochemical cells(TECs)with large Seebeck coefficient can efficiently convert lowgrade heat into electricity,thus having attracted considerable attention in recent years.Utilizing hydrogel electrolyte essentially addresses the electrolyte leakage and complicated packaging issues existing in conventional liquid-based TECs,which well satisfies the need for flexibility.Whereas,the concern of mechanical robustness to ensure stable energy output remains yet to be addressed.Herein,a flexible quasisolid-state TEC is proposed based on the rational design of a hydrogel electrolyte,of which the thermogalvanic effect and mechanical robustness are simultaneously regulated via the multivalent ions of a redox couple.The introduced redox ions not only endow the hydrogel with excellent heat-to-electricity conversion capability,but also act as ionic crosslinks to afford a dual-crosslinked structure,resulting in reversible bonds for effective energy dissipation.The optimized TEC exhibits a high Seebeck coefficient of 1.43 mV K−1 and a significantly improved fracture toughness of 3555 J m^(−2),thereby can maintain a stable thermoelectrochemical performance against various harsh mechanical stimuli.This study reveals the high potential of the quasi-solid-state TEC as a flexible and durable energy supply system for wearable applications.

Transcriptome Profiling of Abscisic Acid-Related Pathways in SNAC4/9-Silenced Tomato Fruits

The NAC(NAM,ATAF,and CUC)family is considered one of the largest families of plant transcription factor,and its members are involved in fruit ripening.Abscisic acid(ABA)has been demonstrated to modulate the fruit ripening process.By applying the virus-induced gene silencing method and next-generation sequencing technology,we conducted a compara-tive analysis of the eff ects of SNAC4(SlNAC48,accession number:NM 001279348.2)and SNAC9(SlNAC19,accession number:XM 004236996.2)on tomato fruit ripening.The results of high-throughput sequencing identified 1262 significant(p<0.05)diff erentially expressed genes(DEGs)in SNAC4-silenced fruit compared to control fruit,while 655 DEGs were identified in SNAC9-silenced fruit.In addition,we selected 26 and 30 significant DEGs(p<0.05 and log 2-fold change>1.0)related to ABA in SNAC4-silenced and SNAC9-silenced tomatoes,respectively,for further analysis.The XET gene and two other genes(E8 and EXP1)were significantly down and upregulated in SNAC4-silenced tomatoes,respectively.However,the PYL9 gene and four other genes(PP2C,CYP707A2,EXPA6,and ACS6)were significantly down and upregulated in SNAC9-silenced tomatoes,respectively.In addition,ten DEGs were selected for use in tests to confirm the accuracy of the transcriptomic results by quantitative real-time polymerase chain reaction(qRT-PCR).Our results highlight the relationship between SNAC4/9 and ABA in the regulation of tomato ripening,which may help provide a theoretical basis for further research on the mechanisms of tomato fruit ripening and senescence.

Flexible nanocomposite electrodes with optimized hybrid structure for improved low-grade heat harvest via thermocells

Thermal energy is ubiquitous and constantly generated in nature and society.Thermocells(TECs)represent a promising energyconversion technology that can directly translate thermal energy into electricity with a large thermopower,thus having attracted considerable attention in recent years.Nevertheless,the use of noble platinum electrodes in TECs has substantially limited their widespread applications,as the scarcity of platinum element increases the cost of materials,and its intrinsic rigidity is not conducive to flexible and wearable applications under heat sources with complex surface geometry.Herein,we propose a facile hybridizing route to constructing flexible electrodes with optimized nanostructures.The flexible composite electrode is fabricated by decorating a single-walled carbon nanotube network with conducting polypyrrole nanospheres through controlled electrochemical deposition.With refined interfacial nanostructures,the resultant composite film can facilitate carrier transport/transfer at the electrolyte-electrode interface,and thereby shows superior overall thermoelectrochemical performance to noble platinum electrode.The TEC employing the flexible composite electrodes yields a maximum output power of 2.555μW under the temperature difference of 30 K,and a device comprising 6 TEC units is assembled to efficiently utilize waste heat and human body heat,revealing the high potential of low-grade heat harvesting.

A Wavy-Structured Highly Stretchable Thermoelectric Generator with Stable Energy Output and Self-Rescuing Capability

Thermoelectric generators(TEGs)demonstrate great potential for flexible and wearable electronics due to the direct electrical energy harvested from waste heat.Good wearability requires high mechanical flexibility and preferable stretchability,while current TEGs are primarily developed with rigid or non-stretchable components,which do not conform well to human skin or accommodate human motions,thus hindering further applications.