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Showing papers on "Conductivity published in 2022"


Journal ArticleDOI
TL;DR: In this paper , a family of fluorinated-1,2-diethoxyethanes as electrolyte solvents were designed and synthesized, which achieved high conductivity, low and stable overpotential, >99.5% Li||Cu half-cell efficiency (up to 99.9%, ± 0.1% fluctuation) and fast activation (Li efficiency > 99.3% within two cycles).
Abstract: Electrolyte engineering improved cycling of Li metal batteries and anode-free cells at low current densities; however, high-rate capability and tuning of ionic conduction in electrolytes are desirable yet less-studied. Here, we design and synthesize a family of fluorinated-1,2-diethoxyethanes as electrolyte solvents. The position and amount of F atoms functionalized on 1,2-diethoxyethane were found to greatly affect electrolyte performance. Partially fluorinated, locally polar –CHF2 is identified as the optimal group rather than fully fluorinated –CF3 in common designs. Paired with 1.2 M lithium bis(fluorosulfonyl)imide, these developed single-salt-single-solvent electrolytes simultaneously enable high conductivity, low and stable overpotential, >99.5% Li||Cu half-cell efficiency (up to 99.9%, ±0.1% fluctuation) and fast activation (Li efficiency >99.3% within two cycles). Combined with high-voltage stability, these electrolytes achieve roughly 270 cycles in 50-μm-thin Li||high-loading-NMC811 full batteries and >140 cycles in fast-cycling Cu||microparticle-LiFePO4 industrial pouch cells under realistic testing conditions. The correlation of Li+–solvent coordination, solvation environments and battery performance is investigated to understand structure–property relationships. Cycling capability, especially at high rates, is limited for lithium metal batteries. Here the authors report electrolyte solvent design through fine-tuning of molecular structures to address the cyclability issue and unravel the electrolyte structure–property relationship for battery applications.

203 citations


Journal ArticleDOI
TL;DR: In this paper , a family of fluorinated-1,2-diethoxyethanes as electrolyte solvents were designed and synthesized, which achieved high conductivity, low and stable overpotential, >99.5% Li||Cu half-cell efficiency (up to 99.9%, ± 0.1% fluctuation) and fast activation (Li efficiency > 99.3% within two cycles).
Abstract: Electrolyte engineering improved cycling of Li metal batteries and anode-free cells at low current densities; however, high-rate capability and tuning of ionic conduction in electrolytes are desirable yet less-studied. Here, we design and synthesize a family of fluorinated-1,2-diethoxyethanes as electrolyte solvents. The position and amount of F atoms functionalized on 1,2-diethoxyethane were found to greatly affect electrolyte performance. Partially fluorinated, locally polar –CHF2 is identified as the optimal group rather than fully fluorinated –CF3 in common designs. Paired with 1.2 M lithium bis(fluorosulfonyl)imide, these developed single-salt-single-solvent electrolytes simultaneously enable high conductivity, low and stable overpotential, >99.5% Li||Cu half-cell efficiency (up to 99.9%, ±0.1% fluctuation) and fast activation (Li efficiency >99.3% within two cycles). Combined with high-voltage stability, these electrolytes achieve roughly 270 cycles in 50-μm-thin Li||high-loading-NMC811 full batteries and >140 cycles in fast-cycling Cu||microparticle-LiFePO4 industrial pouch cells under realistic testing conditions. The correlation of Li+–solvent coordination, solvation environments and battery performance is investigated to understand structure–property relationships. Cycling capability, especially at high rates, is limited for lithium metal batteries. Here the authors report electrolyte solvent design through fine-tuning of molecular structures to address the cyclability issue and unravel the electrolyte structure–property relationship for battery applications.

193 citations


Journal ArticleDOI
TL;DR: Li2InxSc0.666−xCl4 (0 ≤ x ≤ 0.666) is a family of mixed-metal halospinel electrolytes that exhibits promising properties for high-performance solid-state batteries as discussed by the authors .
Abstract: All-solid-state Li batteries (ASSBs) employing inorganic solid electrolytes offer improved safety and are exciting candidates for next-generation energy storage. Herein, we report a family of lithium mixed-metal chlorospinels, Li2InxSc0.666−xCl4 (0 ≤ x ≤ 0.666), with high ionic conductivity (up to 2.0 mS cm−1) owing to a highly disordered Li-ion distribution, and low electronic conductivity (4.7 × 10−10 S cm−1), which are implemented for high-performance ASSBs. Owing to the excellent interfacial stability of the SE against uncoated high-voltage cathode materials, ASSBs utilizing LiCoO2 or LiNi0.85Co0.1Mn0.05O2 exhibit superior rate capability and long-term cycling (up to 4.8 V versus Li+/Li) compared to state-of-the-art ASSBs. In particular, the ASSB with LiNi0.85Co0.1Mn0.05O2 exhibits a long life of >3,000 cycles with 80% capacity retention at room temperature. High cathode loadings are also demonstrated in ASSBs with stable capacity retention of >4 mAh cm−2 (~190 mAh g−1). Intensive research is underway to develop solid-state electrolytes for rechargeable batteries. Here the authors report a family of mixed-metal halospinel electrolytes that exhibits promising properties for high-performance solid-state batteries.

150 citations


Journal ArticleDOI
TL;DR: Li2InxSc0.666−xCl4 (0 ≤ x ≤ 0.666) is a family of mixed-metal halospinel electrolytes that exhibits promising properties for high-performance solid-state batteries as discussed by the authors .
Abstract: All-solid-state Li batteries (ASSBs) employing inorganic solid electrolytes offer improved safety and are exciting candidates for next-generation energy storage. Herein, we report a family of lithium mixed-metal chlorospinels, Li2InxSc0.666−xCl4 (0 ≤ x ≤ 0.666), with high ionic conductivity (up to 2.0 mS cm−1) owing to a highly disordered Li-ion distribution, and low electronic conductivity (4.7 × 10−10 S cm−1), which are implemented for high-performance ASSBs. Owing to the excellent interfacial stability of the SE against uncoated high-voltage cathode materials, ASSBs utilizing LiCoO2 or LiNi0.85Co0.1Mn0.05O2 exhibit superior rate capability and long-term cycling (up to 4.8 V versus Li+/Li) compared to state-of-the-art ASSBs. In particular, the ASSB with LiNi0.85Co0.1Mn0.05O2 exhibits a long life of >3,000 cycles with 80% capacity retention at room temperature. High cathode loadings are also demonstrated in ASSBs with stable capacity retention of >4 mAh cm−2 (~190 mAh g−1). Intensive research is underway to develop solid-state electrolytes for rechargeable batteries. Here the authors report a family of mixed-metal halospinel electrolytes that exhibits promising properties for high-performance solid-state batteries.

144 citations



Journal ArticleDOI
TL;DR: Li5Cr7Ti6O6O25/C nanofibers were constructed by electrospinning method to enhance the kinetic, which realized high cycling stability as mentioned in this paper .

81 citations


Journal ArticleDOI
TL;DR: Li et al. as discussed by the authors exploited hierarchical nanohybrids via ionic hetero-assembly of 3D FeNi-LDH arrays on 2D Ti3C2Tx-based MXene nanosheets through mutual coupling synergy.

80 citations


Journal ArticleDOI
TL;DR: Li et al. as discussed by the authors exploited hierarchical nanohybrids via ionic hetero-assembly of 3D FeNi-LDH arrays on 2D Ti3C2Tx-based MXene nanosheets through mutual coupling synergy.

80 citations


Journal ArticleDOI
TL;DR: In this paper , a series of bi/multimetallic MOF•74 family materials in situ grown on carbon cloth (CC) by doping Mx+ ions in Ni•MOF−74 is fabricated: NiM−MOF@CC (M = Mn2+, Co2+, Cu2+, Zn2+, Al3+, Fe3+).
Abstract: Limited by single metal active sites and low electrical conductivity, designing nickel‐based metal–organic framework (MOF) materials with high capacity and high energy density remains a challenge. Herein, a series of bi/multimetallic MOF‐74 family materials in situ grown on carbon cloth (CC) by doping Mx+ ions in Ni‐MOF‐74 is fabricated: NiM‐MOF@CC (M = Mn2+, Co2+, Cu2+, Zn2+, Al3+, Fe3+), and NiCoM‐MOF@CC (M = Mn2+, Zn2+, Al3+, Fe3+). The type and ratio of doping metal ions can be adjusted while the original topology is preserved. Different metal ions are confirmed by X‐ray absorption fine structure (XAFS). Furthermore, these Ni‐based MOF electrodes are directly utilized as cathodes for aqueous nickel–zinc batteries (NZBs). Among all the as‐prepared electrodes, NiCo‐MOF@CC‐3 (NCM@CC‐3), with an optimized Co/Ni ratio of 1:1, exhibits the best electrical conductivity, which is according to the density functional theory (DFT) theoretical calculations. The NCM@CC‐3//Zn@CC battery achieves a high specific capacity of 1.77 mAh cm–2, a high areal energy density of 2.97 mWh cm–2, and high cycling stability of 83% capacity retention rate after 6000 cycles. The synthetic strategy based on the coordination effect of metal ions and the concept of binder‐free electrodes provide a new direction for the synthesis of high‐performance materials in the energy‐storage field.

78 citations



Journal ArticleDOI
29 Jul 2022-Science
TL;DR: Zhang et al. as discussed by the authors used stable organic radicals as the dopant and ionic salts as the doping modulator to achieve power conversion efficiencies (PCE) of perovskite solar cells.
Abstract: Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process and also leads to poor device stability. We developed a new doping strategy for spiro-OMeTAD that avoids post-oxidation by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated radical doping). We achieved PCEs of >25% and much-improved device stability under harsh conditions. The radicals provide hole polarons that instantly increase the conductivity and work function (WF), and ionic salts further modulate the WF by affecting the energetics of the hole polarons. This organic semiconductor doping strategy, which decouples conductivity and WF tunability, could inspire further optimization in other optoelectronic devices. Description A radical doping approach In perovskite solar cells, high power conversion efficiencies (PCEs) are usually obtained with an organic hole transporter called spiro-OMeTAD. This material must be doped to have sufficient conductivity and optimal work function, but the conventional process with lithium organic salts requires a long oxidation step that also affects device stability. Zhang et al. added spiro-OMeTAD biradical precursors that convert into stable organic monoradicals. Combined with ionic salts, this doping strategy formed solar cells with high PCEs (>25%) and improved stability. This approach also allows conductivity and work function to be tuned separately and could be applied in other optoelectronic devices. —PDS Organic radicals and ionic salts enable doping of an organic hole transporter without post-oxidation treatments.

Journal ArticleDOI
TL;DR: In this paper , the morphology and conductivity tuning of FeNi3 alloy can be finely tailored via introducing the graphene carbon dots (GCDs) to improve the performance of OER.


Journal ArticleDOI
TL;DR: In this paper , a self-template self-selectivity and order-in-disorder synergetic engineering strategy was proposed to boost the K+ -storage capacity, rate capability and cyclic stability simultaneously.
Abstract: Defect-rich carbon materials possess high gravimetric potassium storage capability due to the abundance of active sites, but their cyclic stability is limited because of the low reversibility of undesirable defects and the deteriorative conductivity. Herein, in situ defect-selectivity and order-in-disorder synergetic engineering in carbon via a self-template strategy is reported to boost the K+ -storage capacity, rate capability and cyclic stability simultaneously. The defect-sites are selectively tuned to realize abundant reversible carbon-vacancies with the sacrifice of poorly reversible heteroatom-defects through the persistent gas release during pyrolysis. Meanwhile, nanobubbles generated during the pyrolysis serve as self-templates to induce the surface atom rearrangement, thus in situ embedding nanographitic networks in the defective domains without serious phase separation, which greatly enhances the intrinsic conductivity. The synergetic structure ensures high concentration of reversible carbon-vacancies and fast charge-transfer kinetics simultaneously, leading to high reversible capacity (425 mAh g-1 at 0.05 A g-1 ), high-rate (237.4 mAh g-1 at 1 A g-1 ), and superior cyclic stability (90.4% capacity retention from cycle 10 to 400 at 0.1 A g-1 ). This work provides a rational and facile strategy to realize the tradeoff between defect-sites and intrinsic conductivity, and gives deep insights into the mechanism of reversible potassium storage.

Journal ArticleDOI
TL;DR: In this paper , a new piperazine-linked covalent organic framework (COF) was synthesized through the nucleophilic substitution reaction between octaminophthalocyanines and hexadecafluorophthalocalines.
Abstract: A new kind of piperazine-linked covalent organic framework (COF) was synthesized through the nucleophilic substitution reaction between octaminophthalocyanines and hexadecafluorophthalocyanines. The two-dimensional (2D) frameworks are in tetragonally shaped polygon sheets, which stack in an AA stacking mode to constitute periodically ordered metallophthalocyanine columns and one-dimensional (1D) microporous channels. The piperazine-linked COFs exhibit excellent chemical stability and permanent porosity. By virtue of the neatly arrayed phthalocyanine columns and inbuilt cationic radicals, the piperazine-linked frameworks are highly conductive. The conductivity values of NiPc-NH-CoPcF8 COF reached up to 2.72 and 12.7 S m-1 for pellet and film samples, respectively. Moreover, this p-type conductive COF exhibited a high carrier mobility of 35.4 cm2 V-1 s-1. Both the electric conductivity and carrier mobility set new records for conductive COFs.


Journal ArticleDOI
TL;DR: In this paper , a polyallylamine-encapsulated PAH metallene with defects and porous structure is easily fabricated by a one-step wet chemical reduction method, which exhibits excellent hydrogen evolution reaction (HER) performance with an overpotential of only 14 mV at 10 mA cm-2, a low Tafel slope of 31.2 mV dec−1, and almost no activity decay after stability test.
Abstract: The design of defects and porous structures into metallene with functional surfaces is highly desired to improve its permeability, surface area, and active sites, but remains a great challenge. In this work, polyallylamine‐encapsulated Ir metallene with defects and porous structure (Ir@PAH metallene) is easily fabricated by a one‐step wet chemical reduction method. The Ir@PAH metallene exhibits excellent hydrogen evolution reaction (HER) performance with an overpotential of only 14 mV at 10 mA cm–2, a low Tafel slope of 31.2 mV dec–1, and almost no activity decay after stability test. The abundant defects and pores as well as several‐atomic‐layer nanosheet structures of Ir@PAH metallene provide a large specific surface area, high conductivity, and efficient mass transport/diffusion. In addition, surface‐functionalized PAH molecules can modulate the electronic structure through strong Ir–N interaction and act as proton carriers to capture hydrogen ions, which is very beneficial for the HER in acidic media. This work provides a useful strategy for the synthesis of the defective and porous metallene with functionalized surfaces for various catalytic applications.

Journal ArticleDOI
TL;DR: In this paper , a core-shell structure of SiO2@Ti3C2Tx by electrostatic assembly and hydrogen bonding was developed to reduce the number of active sites, specific surface area, and conductivity.

Journal ArticleDOI
TL;DR: In this article , a multifunctional modification strategy is proposed to construct N−doped KMn8O16 with abundant oxygen vacancy and large specific surface area (named as N‐KMO) through a facile one-step hydrothermal approach.
Abstract: The development of MnO2 as a cathode for aqueous zinc‐ion batteries (AZIBs) is severely limited by the low intrinsic electrical conductivity and unstable crystal structure. Herein, a multifunctional modification strategy is proposed to construct N‐doped KMn8O16 with abundant oxygen vacancy and large specific surface area (named as N‐KMO) through a facile one‐step hydrothermal approach. The synergetic effects of N‐doping, oxygen vacancy, and porous structure in N‐KMO can effectively suppress the dissolution of manganese ions, and promote ion diffusion and electron conduction. As a result, the N‐KMO cathode exhibits dramatically improved stability and reaction kinetics, superior to the pristine MnO2 and MnO2 with only oxygen vacancy. Remarkably, the N‐KMO cathode delivers a high reversible capacity of 262 mAh g−1 after 2500 cycles at 1 A g−1 with a capacity retention of 91%. Simultaneously, the highest specific capacity can reach 298 mAh g−1 at 0.1 A g−1. Theoretical calculations reveal that the oxygen vacancy and N‐doping can improve the electrical conductivity of MnO2 and thus account for the outstanding rate performance. Moreover, ex situ characterizations indicate that the energy storage mechanism of the N‐KMO cathode is mainly a H+ and Zn2+ co‐insertion/extraction process.

Journal ArticleDOI
TL;DR: In this paper, the role of carbon in the cathode mixture is unraveled at room temperature (RT) and low temperature, and the capacity retention of SSBs using designed cathode without carbon was shown.

Journal ArticleDOI
TL;DR: In this paper , the p-quaterphenyl-containing poly(aryl piperidinium) (PQP-100) was designed and prepared to increase the rigidity and hydrophobicity of aryl ether-free polymer backbones.

Journal ArticleDOI
TL;DR: In this article, the p-quaterphenyl-containing poly(aryl piperidinium) (PQP-100) was designed and prepared to increase the rigidity and hydrophobicity of aryl ether-free polymer backbones.

Journal ArticleDOI
TL;DR: In this paper , the role of carbon in the cathode mixture is unraveled at room temperature (RT) and low temperature, and the capacity retention of SSBs using designed cathode without carbon was shown.

Journal ArticleDOI
TL;DR: Ionic conductivity is one of the most critical parameters for superionic conductors to be successfully applied as solid electrolytes in all-solid-state batteries as mentioned in this paper , and various methods have been developed to improve the...
Abstract: Ionic conductivity is one of the most critical parameters for superionic conductors to be successfully applied as solid electrolytes in all-solid-state batteries. Various methods have been developed to improve the...

Journal ArticleDOI
TL;DR: In this paper, a facile calcination process was proposed to prepare the composite of VO2 and amorphous N-doped carbon using ultrathin V6O13 nanobelts coated with polydopamine as precursors.

Journal ArticleDOI
01 Mar 2022
TL;DR: In this paper , the authors provided a two-step strategy for the synthesis of carbon nanofilm stabilized twisty V2O3 nanorods, including a hydrothermal reaction and a controlled pyrolysis process.
Abstract: Vanadium (V) oxides exhibit low electrical conductivity and poor polarization properties, especially in that V2O3 has low stability and is easily oxidized to higher valence V oxides. To solve this problem, we herein provide a two-step strategy for the synthesis of carbon nanofilm stabilized twisty V2O3 nanorods (V2O3@C), including a hydrothermal reaction and a controlled pyrolysis process. Conductivity tests and electron-spin resonance (ESR) spectra indicate that the coating of carbon nanofilm not only enhances the electrical conductivity but also generates abundant defects. The electromagnetic waves absorption (EMA) results suggest that V2O3@C exhibits excellent EMA performance at ultra-low thickness, where the effective absorption bandwidth gets to 7.21 GHz at 1.7 mm and the maximal absorption reaches –56 dB. Enhanced conductivity loss and improved multiple polarization relaxation were used to illustrate the absorbing mechanism of V2O3@C. This work provides new insights into the design of advanced nanocomposites for EMA applications.

Journal ArticleDOI
TL;DR: In this article , a review summarizes the recent progresses in the high temperature proton exchange membrane fuel cells (HT-PEMFCs) and addresses the challenges and promising directions for further development of HT-pEMs.

Journal ArticleDOI
TL;DR: In this paper , a simple and environmentally friendly strategy is proposed to improve the through-plane thermal conductivity of epoxy composites using a 3D boron nitride (3D-BN) framework.
Abstract: Thermally conductive and electrically insulating materials have attracted much attention due to their applications in the field of microelectronics, but through-plane thermal conductivity of materials is still low at present. In this paper, a simple and environmentally friendly strategy is proposed to improve the through-plane thermal conductivity of epoxy composites using a 3D boron nitride (3D-BN) framework. In addition, the effect of filler sizes in 3D-BN skeletons on thermal conductivity was investigated. The epoxy composite with larger BN in lateral size showed a higher through-plane thermal conductivity of 2.01 W/m·K and maintained a low dielectric constant of 3.7 and a dielectric loss of 0.006 at 50 Hz, making it desirable for the application in microelectronic devices.

Journal ArticleDOI
TL;DR: In this paper , the authors report the extreme toughening of hydrogels via the synergistic effect of cations and anions, without the need for specific structure design or adding other reinforcements.
Abstract: Ion is one of the most common additives that can impart electrical conductivity to insulating hydrogels. The concurrent toughening effect of ions, however, is often neglected. This work reports the extreme toughening of hydrogels via the synergistic effect of cations and anions, without the need for specific structure design or adding other reinforcements. The strategy is to equilibrate a physical double network hydrogel consisting of both multivalent cation‐ and kosmotropic anion‐sensitive polymers in specific salt solutions that can induce cross‐linking and salting‐out simultaneously. Both effects are proven positive to boost the mechanical performance and electrical conductivity of the original weak gel, and result in a tough conductive gel with exceptional physical properties, achieving significant enhancements in fracture stress, fracture energy, and ionic conductivity by up to 530‐, 1100‐, and 4.9‐folds, respectively. The optimal fracture stress and toughness reach approximately 15 MPa and 39 kJ m–2, exceeding most state‐of‐the‐art tough conductive hydrogels. Meanwhile, a satisfactory ionic conductivity of 1.5 S m–1 is attained. The presented simple strategy is also found generalizable to other salt ions and polymers, which is expected to expand the applicability of hydrogels to conditions involving demanding mechanical durability.

Journal ArticleDOI
Xiangdong Wang1, Rong Ran1, Xiaoyu Wang1, Menghan Pi1, Rong Ran1 
TL;DR: In this article, a simple method to embed hydroxyethyl cellulose (HEC) into polyvinyl alcohol (PVA) hydrogel to form large pores that can adsorb ions was proposed.