Regulating electrostatic phenomena by cationic polymer binder for scalable high-areal-capacity Li battery electrodes

Three-dimensional high-aspect-ratio microarray thick electrodes for high-rate hybrid supercapacitors

Hybrid supercapacitors (HSCs) with facile integration and high process compatibility are considered ideal power sources for portable consumer electronics. However, as a crucial component for storing energy, traditional thin-film electrodes exhibit low energy density. Although increasing the thickness of thin films can enhance the energy density of the electrodes, it gives rise to issues such as poor mechanical stability and long electron/ion transport pathways. Constructing a stable three-dimensional (3D) ordered thick electrode is considered the key to addressing the aforementioned contradictions. In this work, a manufacturing process combining lithography and chemical deposition techniques is developed to produce large-area and high-aspect-ratio 3D nickel ordered cylindrical array (NiOCA) current collectors. Positive electrodes loaded with nickel-cobalt bimetallic hydroxide (NiOCA/NiCo-LDH) are constructed by electrodeposition, and HSCs are assembled with NiOCA/nitrogen-doped porous carbon (NiOCA/NPC) as negative electrodes. The HSCs exhibits 55% capacity retention with the current density ranging from 2 to 50 mA cm-2. Moreover, it maintains 98.2% of the initial capacity after long-term cycling of 15,000 cycles at a current density of 10 mA cm-2. The manufacturing process demonstrates customizability and favorable repeatability. It is anticipated to provide innovative concepts for the large-scale production of 3D microarray thick electrodes for high-performance energy storage system.

Regulating Anode-Electrolyte Interphasial Reactions by Zwitterionic Binder Chemistry in Lithium-Ion Batteries with High-Nickel Layered Oxide Cathodes and Silicon-Graphite Anodes

The practical application of silicon (Si)-based anodes faces challenges due to severe structural and interphasial degradations. These challenges are exacerbated in lithium-ion batteries (LIBs) employing Si-based anodes with high-nickel layered oxide cathodes, as significant transition-metal crossover catalyzes serious parasitic side reactions, leading to faster cell failure. While enhancing the mechanical properties of polymer binders has been acknowledged as an effective means of improving solid-electrolyte interphase (SEI) stability on Si-based anodes, an in-depth understanding of how the binder chemistry influences the SEI is lacking. Herein, a zwitterionic binder with an ability to manipulate the chemical composition and spatial distribution of the SEI layer is designed for Si-based anodes. It is evidenced that the electrically charged microenvironment created by the zwitterionic species alters the solvation environment on the Si-based anode, featuring rich anions and weakened Li+-solvent interactions. Such a binder-regulated solvation environment induces a thin, uniform, robust SEI on Si-based anodes, which is found to be the key to withstanding transition-metal deposition and minimizing their detrimental impact on catalyzing electrolyte decomposition and devitalizing bulk Si. As a result, albeit possessing comparable mechanical properties to those of commercial binders, the zwitterionic binder enables superior cycling performances in high-energy-density LIBs under demanding operating conditions.

Biomimetic Transparent Slippery Surface for the Locomotion of Photocontrol Droplets and Bubbles

Directed transportation and collection of liquids and bubbles play a vital role in the survival of ecosystems. Among them, the optical response control is widely used in the fields of microfluidic chips and chemical synthesis because of its high remote operation and fast response speed. However, due to poor light transmission, the development direction of traditional near-infrared (NIR) absorbing materials in the field of visualization is limited, and there are few reports of manufacturing an operating platform that can realize the directional movement of droplets/bubbles on a single platform. Here, a transparent photo-responsive PBFS platform is prepared for droplet and bubble manipulation by coating the etched glass substrate with Prussian blue (PB) nanocubes. When near-infrared (NIR) irradiation on the PBFS platform, PB nanocubes trigger heat production by photothermal means, due to the action of Marangoni force, the surface tension on the left and right sides of the droplets and bubbles is not uniform, forming a surface tension gradient, thereby driving the movement of the droplets and bubbles. The control platform has good application potential in the field of microchemical reaction and biomedical engineering and brings new solutions to the field of transparent photothermal materials.

Chelated Metal-Organic Frameworks for Improved the Performance of High-Nickel Cathodes in Lithium-Ion Batteries

Lithium-ion batteries have gained widespread use in various applications, including portable devices, electric vehicles, and energy storage systems. High Ni cathode, LiNixCoyMnzO2 (NCM, x≥0.8, x+y+z=1), have garnered significant attention owing to their high energy density. However, the limited Li-ion transfer rate and transition metal cross-talk to anode pose obstacles to further improvement of electrochemical performance. To tackle these challenges, metal-organic frameworks (MOFs) with chelating agents are employed as additive materials for electrode. MOFs with chelating agents offer three key attributes: (1) Effective mitigation of transition metal cross-talk to the anode, (2) Partial desolvation of Li+ ions through MOF pores, and (3) Immobilization of anions via metal sites in the MOF. Leveraging these advantages, the chelating MOF-modified NCM cathode demonstrates reduced charge transfer resistance, both in their pristine and cycled states. In addition, they exhibit significantly improved the Li-ion diffusion coefficients after 100 cycles. These findings underscore the potential of MOFs with chelating agents as promising additive materials for enhancing the performance of LIBs.

In Situ Self-Reconfiguration Induced Multifunctional Triple-Gradient Artificial Interfacial Layer toward Long-Life Zn-Metal Anodes

Aqueous Zn-ion batteries featuring with intrinsic safety and low cost are highly desirable for large-scale energy storage, but the unstable Zn-metal anode resulting from uncontrollable dendrite growth and grievous hydrogen evolution reaction (HER) shortens their cycle life. Herein, a feasible in situ self-reconfiguration strategy is developed to generate triple-gradient poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PDDA-TFSI)-Zn5(OH)8Cl2·H2O-Sn (PT-ZHC-Sn) artificial layer. The resulting triple-gradient interface consists of the spherical top layer PT with cation confinement and H2O inhibition, the dense intermediate layer ZHC nanosheet with Zn2+ conduction and electron shielding, and the bottom layer Znophilic Sn metal. The well-designed triple-gradient artificial interfacial layer synergistically facilitates rapid Zn2+ diffusion to regulate uniform Zn deposition and accelerates the desolvation process while suppressing HER. Consequently, the PT-ZHC-Sn@Zn symmetric cell achieves an ultralong lifespan over 6500 h at 0.5 mA cm-2 for 0.5 mAh cm-2. Furthermore, a full battery coupling with MnO2 cathode exhibits a 17.2% increase in capacity retention compared with bare Zn anode after 1000 cycles. The in situ self-reconfiguration strategy is also applied to prepare triple-gradient PT-ZHC-In, and the assembled Zn//Cu cell operates steadily for over 8400 h while maintaining Coulombic efficiency of 99.6%. This work paves the way to designing multicomponent gradient interface for stable Zn-metal anodes.

Tailoring Electric Double Layer by Cation Specific Adsorption for High-Voltage Quasi-Solid-State Lithium Metal Batteries

The interfacial instability of high-nickel layered oxides severely plagues practical application of high-energy quasi-solid-state lithium metal batteries (LMBs). Herein, a uniform and highly oxidation-resistant polymer layer within inner Helmholtz plane is engineered by in situ polymerizing 1-vinyl-3-ethylimidazolium (VEIM) cations preferentially adsorbed on LiNi0.83Co0.11Mn0.06O2 (NCM83) surface, inducing the formation of anion-derived cathode electrolyte interphase with fast interfacial kinetics. Meanwhile, the copolymerization of [VEIM][BF4] and vinyl ethylene carbonate (VEC) endows P(VEC-IL) copolymer with the positively-charged imidazolium moieties, providing positive electric fields to facilitate Li+ transport and desolvation process. Consequently, the Li||NCM83 cells with a cut-off voltage up to 4.5 V exhibit excellent reversible capacity of 130 mAh g-1 after 1000 cycles at 25 °C and considerable discharge capacity of 134 mAh g-1 without capacity decay after 100 cycles at -20 °C. This work provides deep understanding on tailoring electric double layer by cation specific adsorption for high-voltage quasi-solid-state LMBs.

Towards Efficient Polymeric Binders for Transition Metal Oxides-based Li-ion Battery Cathodes

Transition metal oxide cathodes (TMOCs) such as LiNi0.8Mn0.1Co0.1O2 and LiMn1.5Ni0.5O4 have been widely employed in Li-ion batteries (LIBs) owing to superior operating voltages, high reversible capacities and relatively low cost. Nevertheless, despite significant advancements in practical application, TMOC-based LIBs face great challenges such as transition metal dissolution and volume expansion during cycling, which jeopardizes the future advance of high-voltage TMOCs. As a critical component of cathode, polymeric binder acts as a crucial part in maintaining the mechanical and ion/electron conductive integrity between active particles, carbon additives, and the aluminum collector, hence minimizing cathode pulverization during battery cycling. Moreover, Polymeric binder with specialized functions is thought to offer a new solution to enhancing the electrochemical stability of the TMOCs. Therefore, this review aims at providing a comprehensive summary of the ideal requirements, design strategies and recent progress of polymeric binders for TMOCs. Future design perspectives and promising research technologies for advanced binders for high-voltage TMOCs are introduced.