Electrolyte Penetration Research Articles

Na2.60Fe1.70(SO4)3 particles embedded in cross-linked graphene oxide networks as high-performance dual-electrode for sodium-ion batteries

Sodium iron sulfate materials have been initially applied to sodium ion batteries (SIBs) owing to their high operating voltage and stable electrochemical properties, yet poor conductivity and low theoretical capacity limit its commercial development. Herein, we first prepared Na2.60Fe1.70(SO4)3@graphene oxide (GO) composite via a facile solid-phase ball milling strategy, which are Na2.60Fe1.70(SO4)3 particles embedded in cross-linked GO networks. For the cathode of SIBs, the active particles in the material are wrapped with cross-linked GO networks that increases the electrolyte penetration and ion transport channels as well as improves electronic conductivity, resulting in a high operating voltage of 3.74 V and excellent cycle stability (retains over 70 % of capacity after 500 cycles at 8 C). Notably, the as-prepared material could exhibit a reversible capacity of 100 mAh g−1 after 100 cycles at 0.2 C as anode for SIBs. Furthermore, the material was first used to assemble symmetric sodium-ion full cell, demonstrating excellent electrochemical performance (achieving 60 mAh g−1 at 0.2 C). The Na2.60Fe1.70(SO4)3 particles wrapped with cross-linked GO networks offer a simple and effective approach to enhance the performance of SIBs, making an important contribution towards their practical industrial application.

Microstructural Insights into Performance Loss of High-Voltage Spinel Cathodes for Lithium-ion Batteries.

Spinel-structured LiNix Mn2-x O4 (LNMO), with low-cost earth-abundant constituents, is a promising high-voltage cathode material for lithium-ion batteries. Even though extensive electrochemical investigations have been conducted on these materials, few studies have explored correlations between their loss in performance and associated changes in microstructure. Here, down to the atomic scale, the structural evolution of these materials is investigated upon the progressive cycling of lithium-ion cells. Transgranular cracking is revealed to be a key feature during cycling; this cracking is initiated at the particle surface and leads to the penetration of electrolytes along the crack path, thereby increasing particle exposure to the electrolyte. The lattice structure on the crack surface shows spatial variances, featuring a top layer of rock-salt, a sublayer of a Mn3 O4 -like arrangement, and then a mixed-cation region adjacent to the bulk lattice. The transgranular cracking, along with the emergence of local lattice distortion, becomes more evident with extended cycling. Further, phase transformation at primary particle surfaces and void formation through vacancy condensation is found in the cycled samples. All these features collectively contribute to the performance degradation of the battery cells during electrochemical cycling.

Study of the effect of functionalization with inhibitors on the corrosion properties of PEO-coated additive manufactured AlSi10Mg alloy

Plasma electrolytic oxidation (PEO) was carried out on SLM-produced AlSi10Mg alloy using various corrosion inhibitor additives. The study investigated the effects of these additives on microstructural evolution, phase composition, and corrosion behavior by comparing the functionalized coating to a standard base silicate PEO one. The results revealed that, in most cases, the additives significantly altered the coatings' thickness, density, and adherence, leading to improved corrosion resistance due to an enhanced barrier effect over electrolyte penetration. Long-term immersion electrochemical impedance spectroscopy (EIS) tests proved the additives’ corrosion inhibitor capability, as they all were able to enhance coating stability.

Sphere-shaped CuCo2O4 nanostructures battery type electrode for supercapacitor via hydrothermal synthesis approach

Transition metal oxide (TMO) is expected to be a highly competitive electrode material for energy storage applications based on its superior electrical and theoretical capacity in supercapacitors. However, a larger surface area and higher porosity are required to improve the electrode's electrochemical performance for practical applications. The nanostructured CuCo2O4 nanoparticles was prepared via a simple hydrothermal process with increased surface area and favorable active site to promote electrolyte penetration. The optimal hydrothermal reaction time was investigated to allow nanoparticle overgrowth, which will be critical in determining the specific surface area of the electrode material. The CuCo2O4 prepared at 7 h hydrothermal reaction period, (i.e. CCO-7 h) battery type electrode revealed a capacity of 193 F/g (96.5 C/g) at 3 mA/cm2 and capacity retention of 85.9% over 6000 cycles at 15 mA/cm2. Furthermore, the activated carbon and CCO-7 h (CCO//AC) asymmetric supercapacitor (ASC) exhibited energy and power densities of 2.120 Wh/kg and 277 W/kg, respectively with a capacity retention of 64% after 2000 cycles. The binary metal oxide CuCo2O4 with unique morphology could be a promising battery type electrode for supercapacitor device application.

Ultrafine Ni0.85Se nanoparticles encapsulated inside hollow porous carbon spheres and their excellent Na storage performance

As a novel anode material for sodium-ion batteries, ultrafine Ni0.85Se nanoparticles encapsulated inside hollow porous carbon spheres (HPCS@Ni0.85Se) are prepared by impregnating Ni(NO3)2 into HPCSs, calcination and selenization, which is based on the strong capillary effect of HPCSs. Material characterization reveals that Ni0.85Se nanoparticles with a diameter of 5–15 nm are evenly dispersed and intimately coupled to the internal wall of HPCSs, and the content of Ni0.85Se reaches 52.81%. HPCSs as unique reactors and Ni0.85Se carriers improve electronic conductivity of Ni0.85Se, facilitate electrolyte penetration and storage, buffer volume variation of Ni0.85Se, effectively confine Ni0.85Se during long-term cycles. Consequently, HPCS@Ni0.85Se exhibits excellent cycling durability and extraordinary rate capability. High reversible capacities of 341 mA h g−1 at 1 A g−1 after 1000 cycles, 280 mA h g−1 at 5 A g−1 after 2000 cycles and 305 mA h g−1 at 10 A g−1 after 540 cycles are achieved. The reaction kinetics and Na + storage mechanism are further analyzed by galvanostatic intermittent titration technique, cyclic voltammetry and electrochemical impedance spectra measurements. Ex-situ characterizations confirm outstanding structural stability of HPCS@Ni0.85Se. It is demonstrated that HPCS@Ni0.85Se is an excellent anode material, and this unique HPCS-based nanoencapsulation structure is an effective composite strategy for transition metal selenides.

Enhanced Optical Contrast and Switching in Near‐Infrared Electrochromic Devices by Optimizing Conjugated Polymer Oligo(Ethylene Glycol) Sidechain Content and Gel Electrolyte Composition

AbstractA detailed investigation addressing the effects of functionalizing conjugated polymers with oligo(ethylene glycol) (EGn) sidechains on the performance and polymer‐electrolyte compatibility of electrochromic devices (ECDs) is reported. The electrochemistry for a series of donor‐acceptor copolymers having near‐infrared (NIR)‐optical absorption, where the donor fragment is 3,4‐ethylenedioxythiophene (EDOT) or an EGn functionalized bithiophene (g2T) and the acceptor fragment is diketopyrrolopyrrole (DPP) functionalized with branched alkyl or EGn sidechains, is extensively probed. ECDs are next fabricated and it is found that EGn sidechain incorporation must be finely balanced to promote polymer‐electrolyte compatibility and provide efficient ion exchange. Proper electrolyte‐cation pairing and polymer structural tuning affords a 2x increase in optical contrast (from 12% to 24%) and >60x reduction in switching time (from 20 to 0.3 s). Atomic force microscopy (AFM)/grazing incidence wide‐angle X‐ray scattering (GIWAXS) characterization of the polymer film morphology/microstructure reveals that an over‐abundance of EGn sidechains generates large polymer crystallites, which can suppress ion exchange. Lastly, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) indicates sidechain/electrolyte identity does not influence the electrolyte penetration depth into the films, and EGn sidechain inclusion increases electrolyte cation uptake. The material structural design insight and guidelines regarding the polymer‐electrolyte ion insertion/expulsion dynamics reported here should be of significant utility for developing next‐generation mixed ionic‐electronic conducting materials.

Deep Reconstruction of the NiFeSP Nanosheet Catalyst for Large Current-Density Water Oxidation.

Evidence shows that the crucial factor in achieving efficient water electrolysis for hydrogen production is the design and synthesis of electrocatalysts that exhibit both high performance and cost-effectiveness for the oxygen evolution reaction (OER). Herein, the NiFeSP nanosheets were facilely prepared on a Ni foam (NF) substrate through a cost-effective electrodeposition method. The electrode structure composed of nanosheets offers a high density of active sites and superior electrical conductivity, thereby enhancing the efficiency of the OER. In addition, the NiFeSP/NF-600 nanosheets exhibit superhydrophilic and superaerophobic characteristics, which effectively enhance the mass-transfer process by facilitating the penetration of electrolytes and enabling rapid release of gas bubbles. Consequently, NiFeSP/NF-600 demonstrates superior electrocatalytic efficacy for OER, exhibiting an overpotential of 292 mV at a high current density of 500 mA cm-2 as well as an exceptional long-term durability of 100 h. More importantly, the rapid reconstruction of FeOOH and NiOOH species from NiFeSP/NF-600 may be the true active species for OER, which is revealed utilizing in situ Raman spectroscopy in conjunction with ex situ characterization. This study not only offers an ideal "pre-catalyst" for an extremely effective OER but also offers a thorough understanding of the mechanism underlying the structural evolution of electrocatalysts and the identification of their actual active sites.

Honeycomb-Structured MoSe2 /rGO Composites as High-Performance Anode Materials for Sodium-Ion Batteries.

Sodium-ion batteries are a promising substitute for lithium batteries due to the abundant resources and low cost of sodium. Herein, honeycomb-shaped MoSe2 /reduced graphene oxide (rGO) composite materials are synthesized from graphene oxide (GO) and MoSe2 through a one-step solvothermal process. Experiments show that the 3D honeycomb structure provides excellent electrolyte penetration while alleviating the volume change during electrochemical cycling. An anode prepared with MoSe2 /rGO composites exhibits significantly improved sodium-ion storage properties, where a large reversible capacity of 215mAhg-1 is obtained after 2700 cycles at the current density of 30.0Ag-1 or after 5900 cycles at 8.0Ag-1 . When such an anode is paired with Na3 V2 (PO4 )3 to form a full cell, a reversible specific capacity of 107.5mAhg-1 can be retained after 1000 cycles at the current of 1.0Ag-1 . Transmission electron microscopy, X-ray photoelectron spectroscopy and in situ X-ray diffraction (XRD) characterization reveal the reversible storage reaction of Na ions in the MoSe2 /rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique honeycomb microstructure and the use of ether-based electrolytes. This study illustrates that combining rGO with ether-based electrolytes has tremendous potential in constructing high-performance sodium-ion batteries.

Boosted urea electro-oxidation over Ni3N-based nanocomposite via systematic regulation tactic

Exploiting high-efficiency Ni-based materials for electrocatalytic urea oxidation reaction (UOR) is critical for urea-related technologies. The catalytic site density, intrinsic activity, charge transfer, and mass diffusion determine overall electrocatalytic efficiency. Simultaneous modulation over the above four factors promises advanced electrocatalysis, yet challenging. Herein we propose a systematic regulation tactic over composition and geometric structure, constructing a nanocomposite comprising Mn doped Ni3N nanoparticles anchored on reduced graphene oxide (rGO/Mn-Ni3N), achieving elegant integration of four design principles into one, thereby eminently boosting UOR. Particularly, Mn doping in Ni3N can modulate electronic state to induce intrinsic activity regulation. Combining metallic Mn-Ni3N with rGO to engineer hierarchical architecture not only promotes charge transfer, but also enriches active site population. Intriguingly, improved hydrophilicity could impart better electrolyte penetration and gas escape. Consequently, such system-optimized rGO/Mn-Ni3N demonstrates state-of-the-art-level UOR electrocatalysis. This work offers a novel paradigm to create advanced catalysts via systematic and integrated modulation.

In situ lithiation modulation of LiNi0.8Co0.1Mn0.1O2 as bifunctional electrocatalysts for highly efficient overall water splitting

LiNi0.8Co0.1Mn0.1O2 (NCM811) is a common cathode material in lithium-ion batteries (LIBs), and the ever-increasing consumption of large quantities of LIBs raises critical concerns about their recycling. Herein, we propose an in-situ lithiation route to tune the structure and electrocatalytic properties of NCM811 by Li+ intercalation and exfoliation in LIBs. In this strategy, the morphology and microstructure of the lithiated NCM811 can be controlled by a specified discharge voltage. The lithiation modulation effectively converted the large NCM811 particles into many flower-like nanosheets. The resulting nanosheets are interconnected and have a rich porous structure, which is conducive to the complete penetration and diffusion of electrolytes and accelerating the charge transfer rate. Moreover, oxygen vacancies and amorphous regions were induced in the nanosheets to provide more active sites. The novel lithiation-modulated nanosheets demonstrate high activity and bifunctional characteristics for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Specifically, the lithiated NCM811 nanosheets demonstrate a low HER overpotential of 58 mV@10 mA cm−2 and OER overpotential of 222@10 mA cm−2. The assembled electrolytic cell for overall water-splitting requires only 1.74 V to reach 100 mA cm−2 with outstanding durability. This work provides a unique strategy for structural modulation of NCM811 cathode in LIBs as high-performance electrocatalysts for water splitting, and demonstrates a high-value recycle of spent LIB electrodes.

Flexible NiFeP@filter paper electrode for alkaline overall water electrosplitting

The large-scale development of flexible electrode is urgently needed for water electrosplitting. Herein, the common and low-cost filter paper (FP) is utilized as the substrate to adjust the flexible property of the catalytic electrode. Through an electroless plating method, the NiFeP alloys were deposited onto the filter paper, which acted as the flexible and self-supported electrode for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The resultant NiFeP@FPs require low overpotentials of 158 mV for HER and 282 mV for OER to deliver a current density of 10 mA cm−2, and exhibit a good stability of 30 h in 1 M KOH. The synergistic effect of Fe–Ni sites regulates electron structure and boosts the catalytic activity. Benefited from good hydrophilicity and interlaced fiber structure of filter paper, electrolyte penetration and electron transfer in the sample are promoted. The assembled two-electrode electrolyzer only requires 1.814 V to achieve 100 mA cm−2 for overall water splitting and shows excellent stability. This work provides a new strategy for the development of flexible and efficient electrodes for water splitting, which advances the development of wearable electronic devices.

Long-term corrosion of silicon carbide/enamel composite coatings on steel rebars: A microstructure-dependent corrosion behavior

Steel rebar's corrosion greatly affects the durability of reinforced concrete (RC) structures. Recently, enamel coatings have been developed for steel rebar's corrosion protection. Given that the anticorrosion performance of enamel coatings is strongly related to their microstructure, in this study, pure enamel coating (PE) and three silicon carbide/enamel composite coatings with 2.5, 5, and 7.5 wt.% silicon carbide addition (S2.5, S5, and S7.5) were prepared on low-carbon steel rebars, representing four different microstructure states, which are severely cracked with porosity of 6%, partially cracked with porosity of 17%, slightly cracked with porosity of 20%, and uncracked with porosity of 26%. The long-term corrosion behavior of different coated rebars was investigated by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, neutral salt-spray test, and morphological observation to understand the effect of silicon carbide content and coating microstructure on the corrosion behavior. Long-term electrochemical studies (210 days) showed that the Rpor and Rct of S7.5 remained 12 times and 5 times that of PE, respectively, indicating an improved corrosion protection with silicon carbide addition. Combined corrosion studies and microstructure results revealed that the corrosion behavior of enamel coated rebars was closely related to the coating microstructure, especially the pores and microcracks. Furthermore, the competitive mechanism of electrolyte penetration degeneration and “self-healing” like enhancement was proposed to interpret the corrosion evolution modes of different coated rebars. The findings of this work give a deep understanding of the corrosion behavior of silicon carbide/enamel composite coatings and provide a solution for long-life RC structures.

Rational design of redox active amorphous Ni-Mn phosphate anchored on vertical graphene nanohills (VGNHs) for solid-state energy storage device

Transition metal phosphates (TMPs) have generated a lot of attention due to their high power and energy potential. However, pristine TMPs materials have sluggish electrode kinetics limiting their practical application. In this study, a sustainable electrochemical deposition approach has been employed for the facile fabrication of amorphous nickel-manganese phosphate (VG-NMP series) nanostructure on vertical graphene nanohills (VGNHs) covered carbon cloth (CC) substrate. Among as-prepared electrodes, the VG-NMP-4 electrode showed optimal electrochemical characteristics. The high specific capacity of VG-NMP-4 was calculated to be 1068 C g−1 (5.14 F cm−2) at a current density of 3 A g−1 and maintained 97 % capacity for 5000 cycles, which outperformed previously reported TMPs-based electrode materials. The enhanced charge storage capability of VG-NMP was mainly due to the dense edge planes of VGs and many gaps for electrolyte penetration because the exposed edge planes have larger areas than the basal plane surface, due to the synergistic effect between Ni and Mn metal ions. The VG-NMP-4 was further utilized as the cathode and anode in the PVA-KOH gel electrolyte for constructing a symmetric solid-state (SSS) supercapacitor. This SSS device offers great durability of 94 % over 5000 cycles and a supreme energy density of 106.8 Wh kg−1 at a power density of 0.751 kW kg−1. This excellent performance suggests that the amorphous Ni-Mn phosphate@VGNHs-CC nanostructured electrode material would be a promising choice for energy storage appliances.

Aliovalent doping and structural design of MoSe2 with fast reaction kinetics for high-stable sodium-ion half/full batteries

The development of high-quality anode materials is critical for the advancement of sodium-ion batteries (SIBs). MoSe2 is a candidate anode for SIBs, while its inherent limitations, such as the agglomeration of nanosheets, poor electron conductance and mechanical strain due to volume changes during cycling, which can lead to decreased performance and durability in SIBs. To overcome the challenges, a novel aliovalent doping and structural engineering was taken to prepare reduced graphene oxide (rGO) functionalized and phosphorus-doped MoSe2 flake (P-MoSe2@rGO) via in situ growth technique. The unique structural design of P-MoSe2@rGO addresses material limitations and optimizes performance by providing a high conductive grid for ion/electron transfer, a large surface area for full electrolyte penetration, and effective suppression of MoSe2 nanosheet agglomeration and mechanical strain due to volume change during charge/discharge in SIBs. The P-MoSe2@rGO inherits the enhanced electronic conductivity and enlarged layer spacing (from 0.652 to 0.668 nm), which boosts the reaction kinetics and facilitates the insertion/extraction of sodium ions. The P-MoSe2@rGO exhibits excellent long-cycle properties with a high reversible capacity of 384 mAh/g at 2 A/g and 338 mAh/g at 10 A/g after 1450 circulations. Detailed discussion of reaction kinetics is conducted. Theoretical calculations prove that doping of P atoms in MoSe2 reduces the forbidden band gap from 1.443 to 1.397 eV and accelerates ion and electron migration. Furthermore, the full cell P-MoSe2@rGO//Na3V2(PO4)3@C (NVP@C) demonstrates a remarkable cycling durability of 326 mAh/g after 200 cycles and a high energy density of 159.6 Wh kg−1. This process provides a reference for the adjustment and modification of MoSe2 to adapt to high performance SIBs anode.

High-performance flexible energy storage: Decorating wrinkled MXene with in situ grown Cu2O nanoparticles

The precise design and fabrication of electrode materials is important for the development of high-performance flexible supercapacitors. Cu2O/MXene film electrodes with an interconnected conductive network structure are prepared in this work by in situ growth of Cu2O nanoparticles in a Ti3C2Tx dispersion, followed by alkali induction and vacuum filtration. The interconnected crimpled Ti3C2Tx structure produced by alkali induction not only works as the self-supported conductive network of the thin film electrode but also demonstrates sufficient open pores and high surface area, which can promote electrolyte penetration and increase active sites for energy storage. The synergy between Cu2O nanoparticles and the crimpled Ti3C2Tx framework leads to good structural stability and electrochemical performance. The results show that the Cu2O/MXene electrode exhibits a high specific area capacitance of 1518 mF cm−2 in 1 M LiCl electrolyte. In addition, the all-solid-state flexible supercapacitor fabricated with the Cu2O/MXene electrode exhibits excellent cyclic stability and flexibility; the capacity retains 94.3% after 10,000 charge and discharge cycles, and the energy storage performance remains stable after 50 mechanical bending cycles.

Self-Assembled 2D VS2 /Ti3 C2 Tx MXene Nanostructures with Ultrafast Kinetics for Superior Electrochemical Sodium-Ion Storage.

Constructing nanostructures with high structural stability and ultrafast electrochemical reaction kinetics as anodes for sodium-ion batteries (SIBs) is a big challenge. Herein, the robust 2D VS2 / Ti3 C2 Tx MXene nanostructures with the strong Ti─S covalent bond synthesized by a one-pot self-assembly approach are developed. The strong interfacial interaction renders the material of good structural durability and enhanced reaction kinetics. Meanwhile, the enlarged and few-layered MXene nanosheets can be easily obtained according to this interaction, providing a conductive network for sufficient electrolyte penetration and rapid charge transfer. As predicted, the VS2 /MXene nanostructures exhibit an extremely low sodium diffusion barrier confirmed by DFT calculations and small charge transfer impedance evidenced by electrochemical impedance spectroscopy (EIS) analysis. Therefore, the SIBs based on the VS2 /MXene electrode present first-class electrochemical performance with the ultrahigh average initial columbic efficiency of 95.08% and excellent sodium-ion storage capacity of 424.6mAhg-1 even at 10Ag-1 . It also shows an outstanding sodium-ion storage capacity of 514.2mAhg-1 at 1Ag-1 with a capacity retention of nearly 100% within 500 times high-rate cycling. Such impressive performance demonstrates the successful synthesis strategy and the great potential of interfacial interactions for high-performance energy storage devices.

Ultra-thick, dense dual-encapsulated Sb anode architecture with conductively elastic networks promises potassium-ion batteries with high areal and volumetric capacities

Ultra-thick, dense alloy-type anodes are promising for achieving large areal and volumetric performance in potassium-ion batteries (PIBs), but severe volume expansion as well as sluggish ion and electron diffusion kinetics heavily impede their widespread application. Herein, we design highly dense (3.1 ​g ​cm−3) Ti3C2Tx MXene and graphene dual-encapsulated nano-Sb monolith architectures (HD-Sb@Ti3C2Tx-G) with high-conductivity elastic networks (1560 ​S ​m−1) and compact dually encapsulated structures, which exhibit a large volumetric capacity of 1780.2 ​mAh cm−3 (gravimetric capacity: 565.0 ​mAh g−1), a long-term stable lifespan of 500 cycles with 82% retention, and a large areal capacity of 8.6 ​mAh cm−2 (loading: 31 ​mg ​cm−2) in PIBs. Using ex-situ SEM, in-situ TEM, kinetic investigations, and theoretical calculations, we reveal that the excellent areal and volumetric performance mechanism stems from the three dimensional (3D) high-conductivity elastic networks and the dual-encapsulated Sb architecture of Ti3C2Tx and graphene; these effectively mitigate against volume expansion and the pulverization of Sb, offering good electrolyte penetration and rapid ionic/electronic transmission. Ti3C2Tx also decreases the K+ diffusion energy barrier, and the ultra-thick compact electrode ensures volumetric and areal performance. These findings provide a feasible strategy for fabricating ultra-thick, dense alloy-type electrodes to achieve high areal and volumetric capacity energy storage via highly-dense, dual-encapsulated architectures with conductive elastic networks.

Dual function of rare earth carboxylate compounds on the barrier properties and active corrosion inhibition of epoxy coatings on mild steel

In this work, two rare earth carboxylate compounds, lanthanum 4-hydroxycinnamate (La(4-OHcin)3) and yttrium 3-(4-methylbenzoyl)propanoate (Y(mbp)3), were incorporated into bisphenol-based epoxy resin to investigate their effectiveness in coating barrier properties and active corrosion inhibition. EIS results showed that the incorporation of rare earth carboxylate inhibitors significantly improved corrosion resistance compared to the inhibitor free coating, with the global impedance modulus remaining at a level higher than 1 GΩ cm2 after 219 days immersion. Following EIS experiments, cross-sectional views of the coatings exhibited a pore-plugging behavior by rare earth containing precipitates, which reinforced the coating barrier properties and delayed the electrolyte diffusion process. These effects were also reflected from the electrochemical parameters extracted from breakpoint frequency analysis and equivalent circuit modelling. Filiform corrosion experiments for artificially scratched coatings suggest that the addition of rare earth carboxylates effectively suppressed the initiation and growth of filaments as well as the development of the coating delamination front. The active corrosion inhibition is possibly related to the formation of a surface protective film consisting of bimetallic complexes and rare earth metal rich precipitates. The electrochemical measurements and surface analyses evidence the dual function of rare earth carboxylate species for enhancing coating barrier properties against electrolyte penetration and providing active corrosion inhibition for the underlying AS1020 mild steel.

Electrolysis Process-Facilitated Engineering of Primary Particles of Cobalt-Free LiNiO2 for Improved Electrochemical Performance.

The particle morphology of LiNiO2 (LNO), the final product of Co-free high-Ni layered oxide cathode materials, must be engineered to prevent the degradation of electrochemical performance caused by the H2-H3 phase transition. Introducing a small amount of dopant oxides (Nb2O5 as an example) during the electrolysis synthesis of the Ni(OH)2 precursor facilitates the engineering of the primary particles of LNO, which is quick, simple, and inexpensive. In addition to the low concentration of Nb that entered the lattice structure, a combination of advanced characterizations indicates that the obtained LNO cathode material contains a high concentration of Nb in the primary particle boundaries in the form of lithium niobium oxide. This electrolysis method facilitated LNO (EMF-LNO) engineering successfully, reducing primary particle size and increasing particle packing density. Therefore, the EMF-LNO cathode material with engineered morphology exhibited increased mechanical strength and electrical contact, blocked electrolyte penetration during cycling, and reduced the H2-H3 phase transition effects.

Utilization of waste plastics-derived conductive current collector in activated carbon electrodes: Effect of activated carbon deposition method

Hydrothermal deposition (HTD) has been widely studied for nanostructures synthesis on nickel foam. But, HTD of activated carbon (AC) on carbon nanomaterials-based current collectors has been hardly studied. Herein, commercial AC was hydrothermally deposited on our previously prepared waste-plastics-derived current collector. The structural, morphological, and electrochemical properties were greatly improved using HTD. Compared to conventional deposition method, the specific surface area increased from 5.916 m2 g−1 to 23.314 m2 g−1 for HTD electrode. This would result in easy electrolyte penetration on the electrode's surface causing better electrochemical performance. The specific capacitance increased to almost 3 times for HTD method, as hydrothermal deposition resulted in regular particle size and aided in avoiding the use of binder. Therefore, this study gives an initiative to deposit AC, a widely used active material in electrode synthesis, by adopting an environment friendly and equally efficient hydrothermal approach.