Side Reactions Research Articles

Ga-polymer dual interfacial layer modified Li metal for high-energy Li metal batteries

Lithium metal is regarded as the ultimate anode material for its extremely exceptional theoretical capacity and low reduction potential. Unfortunately, its practical utility has been constrained by changings such as the formation of lithium dendrites, volume expansion resulting from host-free structure, and uncontrollable side reactions with electrolyte. To achieve long cycle life, conventional single artificial layer strategy fails to solve due to ununiform lithium deposition problem. Consequently, the adoption of dual interfacial layer on lithium metal has emerged as prevailing strategy. In this study, we present a design of dual interface protective layer that combines a Ga-based liquid metal with the organic polymer Poly (ethylene glycol) diacrylate (PEGDA). This innovative combination offers synergistic benefits, including alleviate the volume effect and suppressing undesired interface side reactions. In practical test, the Li || Li symmetrical cell assembled from PEGDA LiGa dual interfacial layer maintains a low overpotential of 36.8 mV after 1400 h (2 mA cm−2, 2mAh cm−2). Moreover, even at a high rate of 5C, Li || LiNi0.8Co0.1Mn0.1O2 (NCM811, 1.0 mAh cm−2) cell still delivers a discharge capacity of 120 mAh g−1, 1.4 times higher than bare Li. Notably, when integrated into a pouch cell with a LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode (1.52 mAh cm−2), this dual interface layers ensures stable performance over 60 cycles, with a capacity retention of 82 %. In summary, this innovative dual interface layer design offers a promising approach to address the intricate challenges associated with lithium metal protection and interface modification.

Controlling silver deposition morphology on aluminum surfaces: Surfactant modify anisotropy of aluminum surface energy

Faced with the challenge of uncontrollable Ag layer deposition morphology during the preparation of silver-coated aluminum particles (Al/Ag). A simple and nontoxic method involving the introduction of surfactants (PEG, PVP, and gelatin (GEL)) to alter the anisotropy of Al surface energy was proposed to achieve control over Ag deposition morphology. Theoretical calculations indicate that PEG undergoes physisorption to Al, while PVP and GEL can alter the surface energy of specific crystal planes by selectively binding to different crystal facets. This action alters the growth habit of Ag on the Al surface and modulates the Ag deposition behavior, these conclusions align with experimental results. Compared with PEG and PVP, the incorporation of GEL was beneficial for the formation of a conformal Ag layer. This can be attributed to GEL preferentially passivating the highest crystal plane Al (110) surface, forming a buffer layer at the solid-liquid interface, leveling out the Ag deposition rate on various crystal planes, and also effectively inhibiting side reactions, in addition to enhancing the wettability of reaction solution. The Al/Ag particle exhibits excellent electrical conductivity (1.03 × 10−6 Ω·cm) and electromagnetic absorption (−32.5 dB, 1.62 GHz), it is suitable for use as a highly conductive electromagnetic shielding material.

Comparative study on the flame retardancy, pyrolysis behavior, and flame retardant pathways of black phosphorus in polyurethane and polypropylene

Black phosphorus nanosheets (BPns) have gained widespread attention in the field of flame retardancy due to their highly efficient flame-retardant properties achieved with a low addition rate (e.g., 0.4%). However, the pyrolysis pathways of BP in polymers have not yet been elucidated. This work systematically studies the flame retardancy and pyrolysis behavior of BP in oxygen-containing (polyurethane, PU) and oxygen-free (polypropylene, PP) polymers, distinguishing between the gas-phase and the condensed-phase flame retardant effect of BP. Through slow heating and staged heating methods, the condensed phase and gas phase pyrolysis products of BP in PU and PP at different temperatures are compared in detail. The distinct flame retardant pathways of BP in PU and PP are revealed. The results indicate that the oxidation of BP commences with its reaction with atmospheric oxygen, implying that the condensed-phase flame-retardant effect of BP primarily occurs at the polymer surface. In PP, BP mainly functions as a gas-phase flame retardant. In the condensed phase, BP generates phosphate derivatives that cover the substrate surface, providing solely a physical barrier effect. In PU, while BP demonstrates an outstanding gas-phase flame-retardant effect, it also accelerates the early dehydration carbonization of alcohols within the substrate, resulting in the formation of phosphate ester compounds (P–O–C structure) to bolster the thermal stability of residual carbon. Additionally, the side reactions of BP during catalytic carbonization will decrease the thermal stability of ester bonds in PU. This work lays a theoretical foundation for the development and application of BP-based flame retardant systems.

Facile Fabrication of Large-Area CuO Flakes for Sodium-Ion Energy Storage Applications

CuO is recognized as a promising anode material for sodium-ion batteries because of its impressive theoretical capacity of 674 mAh g−1, derived from its multiple electron transfer capabilities. However, its practical application is hindered by slow reaction kinetics and rapid capacity loss caused by side reactions during discharge/charge cycles. In this work, we introduce an innovative approach to fabricating large-area CuO and CuO@Al2O3 flakes through a combination of magnetron sputtering, thermal oxidation, and atomic layer deposition techniques. The resultant 2D CuO flakes demonstrate excellent electrochemical properties with a high initial reversible specific capacity of 487 mAh g−1 and good cycling stability, which are attributable to their unique architectures and superior structural durability. Furthermore, when these CuO flakes are coated with an ultrathin Al2O3 layer, the integration of the 2D structures with outer nanocoating leads to significantly enhanced electrochemical properties. Notably, even after 70 rate testing cycles, the CuO@Al2O3 materials maintain a high capacity of 525 mAh g−1 at a current density of 50 mA g−1. Remarkably, at a higher current density of 2000 mA g−1, these materials still achieve a capacity of 220 mAh g−1. Moreover, after 200 cycles at a current density of 200 mA g−1, a high charge capacity of 319 mAh g−1 is sustained. In addition, a full cell consisting of a CuO@Al2O3 anode and a NaNi1/3Fe1/3Mn1/3O2 cathode is investigated, showcasing remarkable cycling performance. Our findings underscore the potential of these innovative flake-like architectures as electrode materials in high-performance sodium-ion batteries, paving the way for advancements in energy storage technologies.

Surface Encapsulation of Layered Oxide Cathode Material with NiTiO3 for Enhanced Cycling Stability of Na-Ion Batteries

Abstract In Na-ion batteries, O3-type layered oxide cathode materials encounter challenges such as particle cracking, oxygen loss, electrolyte side reactions, and multi-phase transitions during the charge/discharge process. This study focuses on surface coating with NiTiO3 achieved via secondary heat treatment using a coating precursor and the surface material. Through in-situ X-ray diffraction (XRD) and differential electrochemical mass spectrometry (DEMS), along with crystal structure characterizations of post-cycling materials, it was determined that the NiTiO3 coating layer facilitates the formation of a stable lattice structure, effectively inhibiting lattice oxygen loss and reducing side reaction with the electrolyte. This enhancement in cycling stability is evidenced by a capacity retention of approximately 74% over 300 cycles at 1C, marking a significant 30% improvement over the initial sample. Furthermore, notable advancements in rate performance were observed. Experimental results indicate that a stable and robust surface structure substantially enhances the overall stability of the bulk phase, presenting a novel approach for designing layered oxide cathodes with higher energy density.

Inclusion of Anion Additives in the Inner Solvation Shell to Regulate the Composition of Solid Electrolyte Interphase

AbstractAn innovative approach to electrolyte engineering in carbonate electrolytes is introduced by incorporating high donor number dual anion additives into the conventional electrolyte system (1 M NaPF6 EC:PC). The active engagement of anions in the primary solvation shell effectively hinders the reduction of solvent molecules by reducing the Lowest Unoccupied Molecular Orbital (LUMO) of Na+‐solvent‐anion complex as compared to the LUMO of pure solvents or Na+‐solvent complex. The participation of anions leads to the formation of a thinner and an inorganic‐rich Solid Electrolyte Interphase on the hard carbon anode enhancing Initial Coulombic Efficiency and significantly improving its kinetics. Moreover, the system with dual anion additives exhibits oxidative stability up to 4.5 V, effectively mitigating the undesired side reactions at high voltage operation of the layered sodium nickel manganese oxide cathode. The addition of dual anion additives proves instrumental in suppressing structural degradation and transition metal dissolution during the long cycling performance of the layered oxide cathode in a sodium‐ion full cell. The synergistic effects of this dual anion additive added electrolyte on both the anode and the cathode ultimately ensured prolonged cycling of the sodium‐ion full cell. The electrolyte engineering approach outlined in this study opens the door to advancing next‐generation high‐voltage sodium batteries.

Overcoming side reaction effects in the colloidal synthesis of ZnSe/ZnS core/shell quantum dots with an etching strategy

Overcoming side reaction effects in the colloidal synthesis of ZnSe/ZnS core/shell quantum dots with an etching strategy

Enhanced low-temperature resistance of lithium-ion batteries based on methyl propionate-fluorinated ethylene carbonate electrolyte.

Low temperature has been a major challenge for lithium-ion batteries to maintain satisfied electrochemical performance, as it leads to poor rechargeability and low capacity retention. Commercial electrolytes of lithium-ion battery rely heavily on ethylene carbonate (EC), and its high melting point (36.4 °C) severely limits the use of batteries below 0 °C. In this work, we demonstrate that using the low melting point carboxylate of methyl propionate (MP) and vinyl fluorocarbonate (FEC) based electrolyte can overcome the low-temperature cycle limitation. Compared with carbonate electrolytes, MP has lower binding energy with Li+, which is essential to improve the low-temperature performance of the battery, and FEC is an effective component to inhibit the side reaction with the electrode of lithium metal. The carefully formulated MP-based electrolyte can generate a solid electrolyte interface with low resistance and rich in inorganic substances, which is conducive to the smooth diffusion of Li+, allowing the battery to successfully cycle at a high rate of 0.5 C at -20 °C, and giving it a reversible capacity retention rate of 65.3% at -40 °C. This work designs a promising advanced electrolyte and holds the potential to overcome limitations of lithium-ion batteries in harsh conditions.

Research Progress on Energy Storage and Anode Protection of Aqueous Zinc‐Ion Battery

AbstractWith the advantages of high energy density, abundant resources and environmental friendliness, Aqueous Zinc‐ion Batteries (AZIBs) are considered as one of the promising new energy systems. However, its practical application is limited by the problems of irregular dendrite growth and interfacial side reaction in zinc anode. In view of the above problems, relevant researchers have given solutions such as the construction of artificial protective layer and the regulation of substrate structure. This paper summarizes the relevant literatures in order to help the future research of zinc‐ion batteries.

High Safety Electrolyte Design for Enabling High Energy-Density System of LiNi0.8Co0.1Mn0.1O2//Phosphorus by Simultaneously Adjusting Dual Electrode/Electrolyte Interfaces.

The demand for state-of-the-art high-energy-density lithium-ion batteries is increasing. However, the low specific capacity of electrode materials in conventional full-cell systems cannot meet the requirements. Ni-rich layered oxide cathodes such as Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) have a high theoretical specific capacity of 200 mAh g-1, but it is always accompanied by side reactions on the electrode/electrolyte interface. Phosphorus anode possesses a high theoretical specific capacity of 2596 mAh g-1, but it has a huge volume expansion (≈300%). Herein, a highly compatible and secure electrolyte is reported via introducing an additive with a narrow electrochemical window, Lithium difluoro(oxalato)borate (LiDFOB), into 1m LiPF6 EC/DMC with tris (2,2,2-trifluoroethyl) phosphate (TFEP) as a cosolvent. LiDFOB participates in the formation of organic/inorganic hybrid electrode/electrolyte interface layers at both the cathode and anode sides. The side reactions on the surface of the NCM811 cathode and the volume expansion of the phosphorus anode are effectively alleviated. The NCM811//RP full cell in this electrolyte shows high capacity retention of 82% after 150 cycles at a 0.5C rate. Meanwhile, the electrolyte shows non-flammability. This work highlights the importance of manipulating the electrode/electrolyte interface layers for the design of lithium-ion batteries with high energy density.

Inhibiting Residual Solvent Induced Side Reactions in Vinylidene Fluoride-Based Polymer Electrolytes Enables Ultra-Stable Solid-State Lithium Metal Batteries.

Residual solvents in vinylidene fluoride (VDF)-based solid polymer electrolytes (SPEs) have been recognized as responsible for their high ionic conductivity. However, side reactions by the residual solvents with the lithium (Li) metal induce poor stability, which has been long neglected. This study proposes a strategy to achieve a delicate equilibrium between ion conduction and electrode stability for VDF-based SPEs. Specifically, 2,2,2-trifluoro-N,N-dimethylacetamide (FDMA) is developed as the nonside reaction solvent for poly(vinylidene fluoride-co-hexafluoropropylene) (PVHF)-based SPEs, achieving both high ionic conductivity and significantly improved electrochemical stability. The developed FDMA solvent fosters the formation of a stable solid electrolyte interphase (SEI) through interface reactions with Li metal, effectively mitigating side reactions and dendrite growth on the Li metal electrode. Consequently, the Li||Li symmetric cells and Li||LiFePO4 cells demonstrate excellent cycling performance, even under limited Li (20µm thick) supply and high-loading cathodes (>10mg cm-2, capacity >1 mAh cm-2) conditions. The stable Li||LiCoO2 cells operation with a cutoff voltage of 4.48V indicates the high-voltage stability of the developed SPE. This study offers valuable insights into the development of advanced VDF-based SPEs for enhanced lithium metal battery performance and longevity.

Synergetic regulation of SEI mechanics and crystallographic orientation for stable lithium metal pouch cells

The advancement of Li-metal batteries is significantly impeded by the presence of unstable solid electrolyte interphase and Li dendrites upon cycling. Herein, we present an innovative approach to address these issues through the synergetic regulation of solid electrolyte interphase mechanics and Li crystallography using yttrium fluoride/polymethyl methacrylate composite layer. Specifically, we demonstrate the in-situ generation of Y-doped lithium metal through the reaction of composite layer with Li metal, which reduces the surface energy of the (200) plane, and tunes the preferential crystallographic orientation to (200) plane from conventional (110) plane during Li plating. These changes effectively passivate Li metal, thereby significantly reducing undesired side reactions between Li and electrolytes by 4 times. Meanwhile, the composite layer with suitable modulus (~1.02 GPa) can enhance mechanical stability and maintain structural stability of SEI. Consequently, a 4.2 Ah pouch cell with high energy density of 468 Wh kg−1 and remarkable capacity stability of 0.08% decay/cycle is demonstrated under harsh condition, such as high-areal-capacity cathode (6 mAh cm−2), lean electrolyte (1.98 g Ah−1), and high current density (3 mA cm−2). Our findings highlight the potential of reactive composite layer as a promising strategy for the development of stable Li-metal batteries.

Biomimetic Superstructured Interphase for Aqueous Zinc-Ion Batteries.

The practical application of aqueous zinc-ion batteries (AZIBs) is greatly challenged by rampant dendrites and pestilent side reactions resulting from an unstable Zn-electrolyte interphase. Herein, we report the construction of a reliable superstructured solid electrolyte interphase for stable Zn anodes by using mesoporous polydopamine (2D-mPDA) platelets as building blocks. The interphase shows a biomimetic nacre's "brick-and-mortar" structure and artificial transmembrane channels of hexagonally ordered mesopores in the plane, overcoming the mechanical robustness and ionic conductivity trade-off. Experimental results and simulations reveal that the -OH and -NH groups on the surface of artificial ion channels can promote rapid desolvation kinetics and serve as an ion sieve to homogenize the Zn2+ flux, thus inhibiting side reactions and ensuring uniform Zn deposition without dendrites. The 2D-mPDA@Zn electrode achieves an ultralow nucleation potential of 35 mV and maintains a Coulombic efficiency of 99.8% over 1500 cycles at 5 mA cm-2. Moreover, the symmetric battery exhibits a prolonged lifespan of over 580 h at a high current density of 20 mA cm-2. This biomimetic superstructured interphase also demonstrates the high feasibility in Zn//VO2 full cells and paves a new route for rechargeable aqueous metal-ion batteries.

A Simple Organo‐electrocatalysis System for the Chlor‐related Industry

Consuming a substantial quantum of energy (~165 TW h), the chlor‐alkali industry garners considerable scholarly and industrial interest, with the anode reaction involving the oxidation of chloride ions being a paramount determinant of reaction rates. While the dimensionally stable anode (DSA) displays commendable catalytic activity and longevity, they rely on precious metals and exhibit a non‐negligible side reaction in sodium hypochlorite (NaClO) production, underscoring the appeal of metal‐free alternatives. However, the molecules and systems currently available are characterized by intricate complexity and are not amenable to large‐scale production. Herein, we have successfully developed an economical and highly efficient molecular catalyst, demonstrating superior performance compared with the former organic molecules in the chloride ion oxidation process (COP) for the production of both chlorine gas (Cl2) and NaClO. The molecule of 2N only needs 92 mV to reach a current density of 1000mA cm‐2, with a small cost of only 0.002 $ g‐1. Furthermore, we propose a novel mechanism underpinned by non‐covalent interactions, serving as the foundation for an innovative approach to the design of efficient anodes for the COP.

A Simple Organo-electrocatalysis System for the Chlor-related Industry.

Consuming a substantial quantum of energy (~165 TW h), the chlor-alkali industry garners considerable scholarly and industrial interest, with the anode reaction involving the oxidation of chloride ions being a paramount determinant of reaction rates. While the dimensionally stable anode (DSA) displays commendable catalytic activity and longevity, they rely on precious metals and exhibit a non-negligible side reaction in sodium hypochlorite (NaClO) production, underscoring the appeal of metal-free alternatives. However, the molecules and systems currently available are characterized by intricate complexity and are not amenable to large-scale production. Herein, we have successfully developed an economical and highly efficient molecular catalyst, demonstrating superior performance compared with the former organic molecules in the chloride ion oxidation process (COP) for the production of both chlorine gas (Cl2) and NaClO. The molecule of 2N only needs 92 mV to reach a current density of 1000mA cm-2, with a small cost of only 0.002 $ g-1. Furthermore, we propose a novel mechanism underpinned by non-covalent interactions, serving as the foundation for an innovative approach to the design of efficient anodes for the COP.

Ultra‐High Proportion of Grain Boundaries in Zinc Metal Anode Spontaneously Inhibiting Dendrites Growth

Aqueous Zn‐ion batteries are an attractive electrochemical energy storage solution for their budget and safe properties. However, dendrites and uncontrolled side reactions in anodes detract the cycle life and energy density of the batteries.Grain boundaries in metals are generally considered as the source of the above problems but we present a diverse result. This study introduces an ultra‐high proportion of grain boundaries on zinc electrodes through femtosecond laser bombardment to enhance stability of zinc metal/electrolyte interface.The ultra‐high proportion of grain boundaries promotes the homogenization of zinc growth potential, to achieve uniform nucleation and growth, thereby suppressing dendrite formation. Additionally, the abundant active sites mitigate the side reactions during the electrochemical process. Consequently, the 15‐μm‐Fs‐Zn||MnO2 pouch cell achieves an energy density of 249.4 Wh kg–1 and operates for over 60 cycles at a depth‐of‐discharge of 23%. The recognition of the favorable influence exerted by UP‐GBs paves a new way for other metal batteries.

Ultra-High Proportion of Grain Boundaries in Zinc Metal Anode Spontaneously Inhibiting Dendrites Growth.

Aqueous Zn-ion batteries are an attractive electrochemical energy storage solution for their budget and safe properties. However, dendrites and uncontrolled side reactions in anodes detract the cycle life and energy density of the batteries.Grain boundaries in metals are generally considered as the source of the above problems but we present a diverse result. This study introduces an ultra-high proportion of grain boundaries on zinc electrodes through femtosecond laser bombardment to enhance stability of zinc metal/electrolyte interface.The ultra-high proportion of grain boundaries promotes the homogenization of zinc growth potential, to achieve uniform nucleation and growth, thereby suppressing dendrite formation. Additionally, the abundant active sites mitigate the side reactions during the electrochemical process. Consequently, the 15-μm-Fs-Zn||MnO2 pouch cell achieves an energy density of 249.4 Wh kg-1 and operates for over 60 cycles at a depth-of-discharge of 23%. The recognition of the favorable influence exerted by UP-GBs paves a new way for other metal batteries.

Assembled MXene-Liquid Metal Cages on Silicon Microparticles as Self-Healing Battery Anodes.

In pursuit of higher energy density in lithium-ion batteries, silicon (Si) has been recognized as a promising candidate to replace commercial graphite due to its high theoretical capacity. However, the pulverization issue of Si microparticles during lithiation/delithiation results in electrical contact loss and increased side reactions, significantly limiting its practical applications. Herein, we propose to utilize liquid metal (LM) particles as the bridging agent, which assemble conductive MXene (Ti3C2Tx) sheets via coordination chemistry, forming cage-like structures encapsulating mSi particles as self-healing high-energy anodes. Due to the integration of robust Ti3C2Tx sheets and deformable LM particles as conductive buffering cages, simultaneously high-rate capability and cyclability can be realized. Post-mortem analysis revealed the cage structural integrity and the maintained electrical percolating network after cycling. This work introduces an effective approach to accommodate structural change via a resilient encapsulating cage and offers useful interface design considerations for versatile battery electrodes.

Antiprotozoal Pt(II) Complexes as Luminophores Bearing Monodentate P/As/Sb-Based Donors: An X-ray Diffractometric, Photoluminescence, and 121Sb-Mössbauer Spectroscopic Study with TD-DFT-Guided Interpretation and Predictive Extrapolation toward Bi.

In this study, it is demonstrated that the radiative rate constant of phosphorescent metal complexes can be substantially enhanced using monodentate ancillary ligands containing heavy donor atoms. Thus, the chlorido coligand from a Pt(II) complex bearing a monoanionic tridentate C^N*N luminophore ([PtLCl]) was replaced by triphenylphosphane (PPh3) and its heavier pnictogen congeners (i.e., PnPh3 to yield [PtL(PnPh3)]). Due to the high tridentate-ligand-centered character of the excited states, the P-related radiative rate is rather low while showing a significant boost upon replacement of the P donor by heavier As- and Sb-based units. The syntheses of the three complexes containing PPh3, AsPh3, and SbPh3 were completed by unambiguous characterization of the clean products using exact mass spectrometry, X-ray diffractometry, bidimensional NMR, and 121Sb-Mössbauer spectroscopy (for [PtL(SbPh3)]) as well as steady state and time-resolved photoluminescence spectroscopies. Hence, it was shown that the hybridization defects of the Vth main-group atoms can be overcome by complexation with the Pt center. Notably, the enhancement of the radiative rate constants mediated by heavier coligands was achieved without significantly influencing the character of the excited states. A rationalization of the results was achieved by TD-DFT. Even though the Bi-based homologue was not accessible due to phenylation side reactions, the experimental data allowed a reasonable extrapolation of the structural features whereas the hybridization defects and the excited state properties related to the Bi-species and its phosphorescence rate can be predicted by theory. The three complexes showed an interesting antiprotozoal activity, which was unexpectedly notorious for the P-containing complex. This work could pave the road toward new efficient materials for optoelectronics and novel antiparasitic drugs.

Self‐Assembled Protection Layer Induced by Bifunctional Additive for Reversible Aqueous Zinc Metal Battery

AbstractAqueous zinc metal battery (AZMB) has received widespread attention due to the advantages of low cost and high safety. However, challenges of dendritic growth, hydrogen evolution reaction, and other side‐reaction impede the performance of the Zn anode. Herein, 4‐amino‐benzene‐sulfonic acid (ABSA) is proposed as an additive to the ZnSO4 electrolyte for improving the performance of AZMB. Combined analyses of theoretical calculations and experiment results, ABSA assumes a pivotal function in constructing an adsorptive layer, facilitating the subsequent formation of a stable sulfur‐rich solid‐electrolyte interphase (SEI). Consequently, the SEI layer modulates the pathway of Zn2+ electrodeposition/dissolution and effectively hinders the deleterious growth of dendrites and unwanted side reactions. As a result, the Zn||Zn cells stably cycles for 2500 h at 1 mAh cm−2/1 mA cm−2 and over 1000 h at 10 mAh cm−2/10 mA cm−2. Significantly, the pouch cell of Zn||VO2 can obtain the specific capacity of 151 mAh g−1 after 100 cycles. This work may provide a new perspective for designing advanced electrolytes from the prospect of interface protection for the AZMB and other metal ion batteries.