Extensive efforts have been devoted to construct a fiber-shaped energystorage device to fulfill the increasing demand for power consumption of textile-based wearable electronics. Despite the myriad of available material selections and device architectures, it is still fundamentally challenging to develop eco-friendly fiber-shaped aqueous rechargeable batteries (FARBs) on a single-fiber architecture with high energy density and long-term stability. Here, we demonstrate flexible and high-voltage coaxialfiber aqueous rechargeable zinc-ion batteries (CARZIBs). By utilizing a novel spherical zinc hexacyanoferrate with prominent electrochemical performance as cathode material, the assembled CARZIB offers a large capacity of 100.2 mAh cm −3 and a high energy density of 195.39 mWh cm −3 , outperforming the state-of-the-art FARBs. Moreover, the resulting CARZIB delivers outstanding flexibility with the capacity retention of 93.2% after bending 3000 times. Last, high operating voltage and output current are achieved by the serial and parallel connection of CARZIBs woven into the flexible textile to power high-energy-consuming devices. Thus, this work provides proof-of-concept design for next-generation wearable energy-storage devices.

The emergence of fiber-shaped supercapacitors (FSSs) has led to a revolution in portable and wearable electronic devices. However, obtaining high energy density FSSs for practical applications is still a key challenge. This article exhibits a facile and effective approach to directly grow well-aligned three-dimensional vanadium nitride (VN) nanowire arrays (NWAs) on carbon nanotube (CNT) fiber with an ultrahigh specific capacitance of 715 mF/cm in a three-electrode system. Benefiting from their intriguing structural features, we successfully fabricated a prototype asymmetric coaxial FSS (ACFSS) with a maximum operating voltage of 1.8 V. From core to shell, this ACFSS consists of a CNT fiber core coated with VN@C NWAs as the negative electrode, NaSO poly(vinyl alcohol) (PVA) as the solid electrolyte, and MnO/conducting polymer/CNT sheets as the positive electrode. The novel coaxial architecture not only fully enables utilization of the effective surface area and decreases the contact resistance between the two electrodes but also, more importantly, provides a short pathway for the ultrafast transport of axial electrons and ions. The electrochemical results show that the optimized ACFSS exhibits a remarkable specific capacitance of 213.5 mF/cm and an exceptional energy density of 96.07 μWh/cm, the highest areal capacitance and areal energy density yet reported in FSSs. Furthermore, the device possesses excellent flexibility in that its capacitance retention reaches 96.8% after bending 5000 times, which further allows it to be woven into flexible electronic clothes with conventional weaving techniques. Therefore, the asymmetric coaxial architectural design allows new opportunities to fabricate high-performance flexible FSSs for future portable and wearable electronic devices.

Iron oxide (FeO) has drawn much attention because of its high theoretical capacitance, wide operating potential window, low cost, natural abundance, and environmental friendliness. However, the inferior conductivity and insufficient ionic diffusion rate of a simple FeO electrode leading to the low specific capacitance and poor rate performance of supercapacitors have impeded its applications. In this work, we report a facile and cost-effective method to directly grow MIL-88-Fe metal-organic framework (MOF) derived spindle-like α-FeO@C on oxidized carbon nanotube fiber (S-α-FeO@C/OCNTF). The S-α-FeO@C/OCNTF electrode is demonstrated with a high areal capacitance of 1232.4 mF/cm at a current density of 2 mA/cm and considerable rate capability with capacitance retention of 63% at a current density of 20 mA/cm and is well matched with the cathode of the Na-doped MnO nanosheets on CNTF (Na-MnO NSs/CNTF). The electrochemical test results show that the S-α-FeO@C/OCNTF//Na-MnO NSs/CNTF asymmetric supercapacitors possess a high specific capacitance of 201.3 mF/cm and an exceptional energy density of 135.3 μWh/cm. Thus, MIL-88-Fe MOF derived S-α-FeO@C will be a promising anode for applications in next-generation wearable asymmetric supercapacitors.

Increased efforts have recently been devoted to developing high-energy-density flexible supercapacitors for their practical applications in portable and wearable electronics. Although high operating voltages have been achieved in fiber-shaped asymmetric supercapacitors (FASCs), low specific capacitance still restricts the further enhancement of their energy density. This article specifies a facile and cost-effective method to directly grow three-dimensionally well-aligned zinc-nickel-cobalt oxide (ZNCO)@Ni(OH) nanowire arrays (NWAs) on a carbon nanotube fiber (CNTF) with an ultrahigh specific capacitance of 2847.5 F/cm (10.678 F/cm) at a current density of 1 mA/cm, These levels are approximately five times higher than those of ZNCO NWAs/CNTF electrodes (2.10 F/cm) and four times higher than Ni(OH)/CNTF electrodes (2.55 F/cm). Benefiting from their unique features, we successfully fabricated a prototype coaxial FASC (CFASC) with a maximum operating voltage of 1.6 V, which was assembled by adopting ZNCO@Ni(OH) NWAs/CNTF as the core electrode and a thin layer of carbon coated vanadium nitride (VN@C) NWAs on a carbon nanotube strip (CNTS) as the outer electrode with KOH poly(vinyl alcohol) (PVA) as the gel electrolyte. A high specific capacitance of 94.67 F/cm (573.75 mF/cm) and an exceptional energy density of 33.66 mWh/cm (204.02 μWh/cm) were achieved for our CFASC device, which represent the highest levels of fiber-shaped supercapacitors to date. More importantly, the fiber-shaped ZnO-based photodetector is powered by the integrated CFASC, and it demonstrates excellent sensitivity in detecting UV light. Thus, this work paves the way to the construction of ultrahigh-capacity electrode materials for next-generation wearable energy-storage devices.

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Silver–zinc (Ag–Zn) batteries are one of the promising aqueous batteries to collect and store solar energy with high energy density, a stable output voltage, and being environmentally benign, but most Ag–Zn batteries have large contact resistance caused by polymer binders and conductive additives, thus leading to their low specific capacity and rate performance. As a proof-of-concept demonstration, we constructed a solar charged planar flexible quasi-solid-state aqueous rechargeable Ag–Zn battery using metal–organic framework (MOF)-derived Ag nanowires on carbon cloth as a binder-free cathode. Our electrochemical results show that the as-fabricated Ag–Zn battery has a remarkable energy density of 1.87 mWh/cm2 because MOF-derived Ag nanowires can provide abundant reaction sites and short electron and ion diffusion paths. Moreover, the as-fabricated Ag–Zn battery integrated with a solar cell can be charged by sunlight. Thus, our findings pave an avenue to develop solar energy-powered portable and wearable electronic devices.

Wearable fiber‐shaped electronic devices have drawn abundant attention in scientific research fields, and tremendous efforts are dedicated to the development of various fiber‐shaped devices that possess sufficient flexibility. However, most studies suffer from persistent limitations in fabrication cost, efficiency, the preparation procedure, and scalability that impede their practical application in flexible and wearable fields. In this study, a simple, low‐cost 3D printing method capable of high manufacturing efficiency, scalability, and complexity capability to fabricate a fiber‐shaped integrated device that combines printed fiber‐shaped temperature sensors (FTSs) with printed fiber‐shaped asymmetric supercapacitors (FASCs) is developed. The FASCs device can provide stable output power to FTSs. Moreover, the temperature responsivity of the integrated device is 1.95% °C−1.

A self-powering, multifunctional, miniaturized integrated system was designed to achieve real-time health monitoring both statically and dynamically.