Structural Engineering of Ultrathin, Lightweight, and Bendable Electrodes Based on a Nanowire Network Current Collector Enables Flexible Energy-Storage Devices

Abstract

Because of the rapid development of portable electronics, there is an urgent need for ultrathin, lightweight, and bendable electrodes for flexible and wearable energy-storage devices (FWESDs). This paper introduces the structural engineering of flexible electrodes with the above characteristics based on a Ag nanowire (NW) network current collector. The conductive interconnected networks give electrodes a highway of electron transport and excellent flexibility. Two kinds of nanostructures have been designed for high-performance electrodes, enabling diverse applications in FWESDs. In a core–shell Ag@NiCo/MnO x NW electrode, the MnO x thin shell layer favors a quick and reversible faradic reaction at the near surface. The electrode achieves a specific capacity of 41 mF cm–2 (350 F g–1), a capacitance retention rate of 88% after 2000 cycles, and stable electrochemical performance under repeated bending. In double-layer Ag@NiCo NW-Co­(OH)2 electrode, the vertical growth of Co­(OH)2 nanosheets covers the entire network, generating a high mass loading and abundant pathways for ion diffusion. As a result, the electrode delivers a high capacity of 376 mF cm–2 (1886 F g–1) and an excellent Coulombic efficiency of 95%. Both electrodes are demonstrated in FWESDs under various working scenarios, indicating promising prospects in the next generation of flexible electronics.

CuxO-Modified Nanoporous Cu Foil as a Self-Supporting Electrode for Supercapacitor and Oxygen Evolution Reaction

“…The electrochemical impedance spectroscopy (EIS) was obtained at open circuit potential in the frequency range from 0.01 Hz to 1 MHz with a 5 mV amplitude. The O-Cu-2h//AC asymmetric supercapacitor was tested via CV under various scan rates of 5, 10, 30, 50, 70, and 100 mV s −1 , between 0.6−1.6 V, as well as GCD under current densities of 2, 3, 4, 5, 6 and 7 mA cm −2 , between 0.6−1.6 V. The calculation details of areal capacitance, specific capacitance, and energy and power densities can be found in references [29,30]. To estimate the mass of Cu x O on the surface, we measured the weight of the dealloyed Cu foils before and after oxidation.…”

Ultralight Porous Cu Nanowire Aerogels as Stable Hosts for High Li-Content Metal Anodes

“…Based on the battery configuration and reaction mechanism, the strategies could be summarized as anode interface engineering (artificial SEI and interface reconstruction), − separator modification engineering, − electrolyte modification engineering, − and anode structure engineering. − Among them, the anode structure engineering, including reconstruction of Li metal and employment of porous current collectors, shows excellent effects in Li dendrite suppression. − Conventional used porous current collectors, including porous carbon nanomaterials and porous metal materials, have been widely investigated to stabilize Li metal anodes. − Compared with carbon-based current collectors, porous metal current collectors with appropriate specific surface areas are more beneficial for uniform distribution of charge density and ion concentration as well as the promotion of sufficient inner space to accommodate the deposition of Li metal and thereby could more effectively suppress the metal dendrite formation. , The introduction of porous metal current collectors has proven to be effective to inhibit Li dendrites and accommodate homogeneous Li deposition, thus pushing the commercial proceedings of highly stabilized Li metal batteries. − However, most reported porous metal hosts usually have small pore volumes and account for more than 83 wt % of the composite anode . The high density of the metal current collector will inevitably increase the portion of the inactive part in the electrode, thereby lowering the energy density of the battery. − Hence, reducing the mass of metal current collectors is significantly important for elevating the energy density of batteries. Exemplified with the graphite anode of Li-ion batteries, the commonly used electrode is composed of 100 μm thickness graphite layers coated on both sides of the 10 μm thickness Cu foil .…”