Five different butynediol-ethoxylate modified polysiloxanes (PSi-EO) were designed and synthesized via two-step reactions: the preparation of low-hydrogen containing silicone oil (LPMHS) by ...acid-catalyzed polymerization and the following hydrosilylation reaction with 1,4-bis(2-hydroxyethoxy)-2-butyne. The chemical composition of each product was confirmed by FT-IR, 1H NMR, and 29Si NMR. The surface activities and aggregation behaviors of PSi-EO surfactants in aqueous solution were studied systematically using surface tension, dynamic light scattering (DLS), transmission electron microscopy (TEM), and contact-angle methodologies. Relatively low critical aggregation concentration (15–34 mg·L–1) and surface tension (∼25 mN·m–1) were measured for PSi-EO aqueous solution. The rate of surface tension reduction increased both with increasing PSi-EO concentration and with increases in the proportion of hydrophilic moieties within the synthesized compounds. Furthermore, DLS and TEM studies revealed that PSi-EO self-assembled in aqueous solution to form spherical aggregates. Contact-angle measurements conducted upon low-energy paraffin film surfaces demonstrated that PSi-EO exhibited efficient spreading at concentrations above the critical aggregation concentration.
The prosperity of smart portable microdevices urgently requires an advanced integrated microsystem equipped with cost‐effective safe microbatteries and ultra‐stable sensitive sensors. However, the ...practical application of smart microdevices is limited by complex active materials with single function. Here, the two‐dimensional (2D) mesoporous nanosheets of polyaniline decorated on graphene with large specific surface area of 141 m2 g−1, ample active sites, comparable conductivity, and ordered mesopores of 18 nm for a new‐type co‐planar integrated microsystem of zinc ion microbattery and gas sensor are developed. These unique triple‐function mesoporous nanosheets are well proved for dendrite‐free zinc anode with long cyclability (>500 h) and small overpotential (48 mV), a high performance cathode of zinc ion microbattery with outstanding volumetric capacity of 78 mAh cm–3 outperforming their counterparts reported, and a highly sensitive gas sensor with a resistance response (ΔR/R0%) of 118% for 20 ppm NH3. Moreover, the co‐planar battery‐sensor integrated microsystem exhibits superior mechanical stability and smart integration. Therefore, this work will open many opportunities to develop multifunctional 2D mesoporous materials for high performance smart integrated microsystems.
2D mesoporous polyaniline/graphene nanosheets serve as multifunctional active materials for an intelligent integrated microsystem of zinc ion microbatteries and gas sensor, accompanied with an effective protective layer for a dendrite‐free zinc anode. The resulting integrated microsystem exhibits highly sensitive response to NH3, high specific capacity, and superior mechanical stability.
Abstract
High‐concentration electrolyte effectively improves the energy density and anti‐freezing property of aqueous micro‐supercapacitors (MSCs), endowing them the opportunity serving as power ...sources for miniaturized electronics. However, the excessive usage of salt significantly increases the cost of the electrolyte. Herein, a cost‐effective moderate‐concentration hybrid electrolyte is designed by introducing CaCl
2
and ethylene glycerol (EG) additives for low‐temperature and high‐voltage MSCs. The results manifest that the introduction of CaCl
2
minimizes the number of water molecules with strong hydrogen bonds while the addition of EG can reduce the amount of H
2
O molecules in the primary solvation shell sheath of Ca
2+
ion and strengthen the hydrogen bonds between EG and water molecules, thus endowing the optimal electrolyte with a wide electrochemical stability window of 3.5 V and a freezing point lower than −120 °C. Furthermore, the resulting hybrid MSCs offer a high voltage of 1.6 V, and realize 62% capacitance retention at −40 °C compared to that at room temperature. Moreover, The MSCs can endure 20000 cycles with 98.5% capacitance retention at −40 °C. This work provides a meaningful guidance for designing low‐cost moderate‐concentration hybrid electrolyte with wide electrochemical stability window and anti‐freezing property for intrinsically safe and environmentally adaptable devices.
The state-of-the-art advances in functional planar micro-supercapacitors and their smart self-powered integrated microsystems are systematically overviewed, and the existing challenges and future ...perspectives are briefly discussed.
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The popularization of portable, implantable and wearable microelectronics has greatly stimulated the rapid development of high-power planar micro-supercapacitors (PMSCs). Particularly, the introduction of new functionalities (e.g., high voltage, flexibility, stretchability, self-healing, electrochromism and photo/thermal response) to PMSCs is essential for building multifunctional PMSCs and their smart self-powered integrated microsystems. In this review, we summarized the latest advances in PMSCs from various functional microdevices to their smart integrated microsystems. Primarily, the functionalities of PMSCs are characterized by three major factors to emphasize their electrochemical behavior and unique scope of application. These include but are not limited to high-voltage outputs (realized through asymmetric configuration, novel electrolyte and modular integration), mechanical resilience that includes various feats of flexibility or stretchability, and response to stimuli (self-healing, electrochromic, photo-responsive, or thermal-responsive properties). Furthermore, three representative integrated microsystems including energy harvester-PMSC, PMSC-energy consumption, and all-in-one self-powered microsystems are elaborately overviewed to understand the emerging intelligent interaction models. Finally, the key perspectives, challenges and opportunities of PMSCs for powering smart microelectronics are proposed in brief.
Lithium‐ion capacitors (LICs) composed of a battery‐type electrode and a capacitor‐type electrode are highly competitive candidates for next‐generation electrochemical energy storage devices, ...simultaneously achieving high energy and power densities. However, the present LICs are still hindered by the imbalance of electrode kinetics and capacity of anode and cathode. Recently, two‐dimensional (2D) materials with unique structure and appealing properties have received extensive attentions for applications in LICs, with remarkable improvements from charge storage capacity to reaction kinetics. Herein, we review the recent advances in the applications of 2D materials for high‐energy and high‐power LICs. The key advantages and important roles of 2D materials are emphasized for the construction of LICs, including electrochemical active materials, ultrathin conductive and flexible supports for hybridization with other active materials, and 2D functional building blocks for assembling macroscopic hierarchical 3D frameworks. Finally, the challenges and prospects associated with the applications of 2D materials for high‐performance LICs are discussed.
2D or not 2D: The recent progress in the applications of 2D materials for high‐energy and high‐power lithium‐ion capacitors are summarized, highlighting the key advantages and important roles of 2D materials for the construction of lithium‐ion capacitors.
Li-ion capacitors (LICs) are promising to simultaneously achieve battery-level energy density and supercapacitor-level power density, but the slow kinetics of diffusion-controlled battery anodes lead ...to unmatched two-electrode kinetics at the device level. Herein, we report a capacitive-dominated anode of two-dimensional (2D) crumpled nitrogen-doped carbon nanosheets (N-CNS) with tailored nitrogen incorporation and abundant mesopore distribution, exhibiting large capacities and superior rate performance. The optimized N-CNS delivers large reversible capacities of 620 and 121 mA h g
−1
at 0.1 and 100 A g
−1
, respectively. The introduced nitrogen is found to contribute to providing additional pseudocapacity and high Li
+
diffusion coefficients in the medium-high voltage region and enhancing the capacitive-dominated charge storage process. The structural reversibility and "adsorption-intercalation" mechanism are supported by
in situ
and
ex situ
measurements. Furthermore, it is theoretically revealed that N-CNS with superior electrochemical properties benefits from the increase in Li
+
adsorption energy and the decline in the Li
+
diffusion barrier. A LIC coupling the N-CNS anode with a porous carbon cathode outputs a high energy density of 75 W h kg
−1
at an ultrahigh power density of 65 kW kg
−1
. This study provides a novel and effective approach to developing high-performance carbon-based anodes for constructing advanced LICs featuring high energy and power density.
The synergistic effect of abundant mesopore distribution and nitrogen doping enables 2D crumpled nitrogen-doped carbon nanosheets as anode materials for Li-ion capacitors with large capacitive-capacities and ultrahigh rate performance.
High‐concentration electrolyte effectively improves the energy density and anti‐freezing property of aqueous micro‐supercapacitors (MSCs), endowing them the opportunity serving as power sources for ...miniaturized electronics. However, the excessive usage of salt significantly increases the cost of the electrolyte. Herein, a cost‐effective moderate‐concentration hybrid electrolyte is designed by introducing CaCl2 and ethylene glycerol (EG) additives for low‐temperature and high‐voltage MSCs. The results manifest that the introduction of CaCl2 minimizes the number of water molecules with strong hydrogen bonds while the addition of EG can reduce the amount of H2O molecules in the primary solvation shell sheath of Ca2+ ion and strengthen the hydrogen bonds between EG and water molecules, thus endowing the optimal electrolyte with a wide electrochemical stability window of 3.5 V and a freezing point lower than −120 °C. Furthermore, the resulting hybrid MSCs offer a high voltage of 1.6 V, and realize 62% capacitance retention at −40 °C compared to that at room temperature. Moreover, The MSCs can endure 20000 cycles with 98.5% capacitance retention at −40 °C. This work provides a meaningful guidance for designing low‐cost moderate‐concentration hybrid electrolyte with wide electrochemical stability window and anti‐freezing property for intrinsically safe and environmentally adaptable devices.
By simultaneously introducing CaCl2 and EG additives into 1 m LiCl electrolyte, a cost‐effective anti‐freezing moderate‐concentration hybrid electrolyte with wide electrochemical window is designed and prepared for planar micro‐supercapacitors featuring high‐voltage and anti‐freezing property, showing significantly increased energy density, and excellent long‐term cycling stability at low‐temperature, indicative of superior environmental adaptability.
Facile synthesis of ultrahigh surface area porous carbons with well‐defined functionalities such as N‐doping remains a formidable challenge as extensive pore creation results in significant damage to ...the active sites. Herein, an ultrahigh surface area, N‐doped hierarchically porous carbon was prepared through a multicomponent co‐assembly approach. The resultant N‐doped hierarchically porous carbon (N‐HPC) possessed an ultrahigh surface area (≈1960 m2 g−1), a uniform interpenetrating micropore (≈1.3 nm) and large mesopore (≈7.6 nm) size, and high N‐doping in the carbon frameworks (≈5 wt %). The N‐HPC exhibited a high specific capacitance (358 F g−1 at 0.5 A g−1) as a supercapacitor electrode in aqueous alkaline electrolyte with a stable cycling performance after10 000 charge/discharge cycles. Moreover, as a CO2 absorbent, N‐HPC displayed an adsorption capacity of 29.0 mmol g−1 at 0 °C under a high pressure of 30 bar.
Doping done right: N‐doped hierarchically porous carbon materials with an ultrahigh specific surface area and high N content are fabricated through a multicomponent co‐assembly method. The SiO2 component provides reinforcement to support a highly ordered mesostructured, acts as a cross‐linked network that can keep confinement of nitridation from pyrolysis, and as a poreforming agent it creates interpenetrating micropores.
