Riding on the rapid growth in electric vehicles and the stationary energy storage market, high‐energy‐density lithium‐ion batteries and next‐generation rechargeable batteries (i.e., advanced ...batteries) have been long‐accepted as essential building blocks for future technology reaching the specific energy density of 400 Wh kg−1 at the cell‐level. Such progress, mainly driven by the emerging electrode materials or electrolytes, necessitates the development of polymeric materials with advanced functionalities in the battery to address new challenges. Therefore, it is urgently required to understand the basic chemistry and essential research directions in polymeric materials and establish a library for the polymeric materials that enables the development of advanced batteries. Herein, based on indispensable polymeric materials in advanced high‐energy‐density lithium‐ion, lithium–sulfur, lithium‐metal, and dual‐ion battery chemistry, the key research directions of polymeric materials for achieving high‐energy‐density and safety are summarized and design strategies for further improving performance are examined. Furthermore, the challenges of polymeric materials for advanced battery technologies are discussed.
Polymeric materials indispensable to building safe, high‐energy‐density advanced batteries, in terms of electrode integrity, interface stability, and extending operational limits, are reviewed. The fundamental understanding of functional polymeric materials for advanced lithium battery chemistry and key research directions are discussed, thus suggesting design strategies for polymeric materials for advanced lithium batteries with improved electrochemical performances.
High‐capacity anode materials are promising candidates for increasing the energy density of lithium (Li)‐ion batteries due to their high theoretical capacities. However, a rapid capacity fading due ...to the huge volume changes during charge‐discharge cycles limits practical applications. Herein, a layering‐charged polymeric binder is introduced that can effectively integrate high‐capacity anodes using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. The charged polymeric binder builds a dynamically charge‐directed network on the active materials with high versatility and efficiently dissipates the electrode stress with its excellent mechanical properties. In addition, poly(ethylene glycol) (PEG) moieties of the charged binder offer a fast Li‐ion conduction pathway that can form an ultra‐thick silicon oxide (SiOx)‐based electrode (≈10.2 mAh cm−2) without compromising the reversible specific capacity and promote effective charge interaction as a mechanical modulator. Such an unprecedented charge‐directed binder provides insights into the rational design of a binder for high‐capacity anodes.
A layering‐charged polymeric binder forms charge‐directed network on the high‐capacity anodes which efficiently dissipates the stress of the electrode using a strong yet reversible Coulomb interaction and enriched hydrogen bonding. Poly(ethylene glycol) (PEG) moieties, as a mechanical modulator, in charged polymer facilitate the Li‐ion conduction which enable the formulation of an ultrathick silicon oxide (SiOx)‐based electrode (≈10.2 mAh cm−2).
Abstract
Li‐ion batteries (LIBs) have wide applications owing to their high‐energy density and stable cycle characteristics. Nevertheless, with the rapid expansion of electric vehicle market, issues ...such as explosion of LIBs and the need to secure a longer driving distance have emerged. In this work, functional metal–organic frameworks (MOFs) are introduced as a separator in LIBs, in which a highly heat‐resistant polymer separator is fabricated through electrospinning. The MOFs can scavenge impurities (including gas, water, and hydrofluoric acid) that positively affect battery performance and safety. The multi‐functional separator suppresses salt decomposition when a nickel‐rich cathode is operated at high voltage and high temperature through it. This delays the deterioration of the cathode interface and results in a superb cycle stability with 75% retention even in the presence of 500 ppm of water in the electrolytes. In addition, the pouch cell is manufactured by enlarging the separator, and the degree of electrode swelling due to gas generation and interface degradation in the pouch state is alleviated to 50% or less. These findings highlight the necessity of scavenging impurities to maintain excellent performance and provides the development direction of functional separators in LIBs.
Flexible lithium‐ion batteries (LIBs) have attracted significant attention owing to their ever‐increasing use in flexible and wearable electronic devices. However, the practical application of ...flexible LIBs in devices has been plagued by the challenge of simultaneously achieving high energy density and high flexibility. Herein, a hierarchical 3D electrode (H3DE) is introduced with high mass loading that can construct highly flexible LIBs with ultrahigh energy density. The H3DE features a bicontinuous structure and the active materials along with conductive agents are uniformly distributed on the 3D framework regardless of the active material type. The bicontinuous electrode/electrolyte integration enables a rapid ion/electron transport, thereby improving the redox kinetics and lowering the internal cell resistance. Moreover, the H3DE exhibits exceptional structural integrity and flexibility during repeated mechanical deformations. Benefiting from the remarkable physicochemical properties, pouch‐type flexible LIBs using H3DE demonstrate stable cycling under various bending states, achieving a record‐high energy density (438.6 Wh kg−1 and 20.4 mWh cm−2), and areal capacity (5.6 mAh cm−2), outperforming all previously reported flexible LIBs. This study provides a feasible solution for the preparation of high‐energy‐density flexible LIBs for various energy storage devices.
A hierarchical 3D electrode design with high mass loading enables the realization of high‐energy‐density flexible batteries. The electrode demonstrates outstanding mechanical flexibility, while the bicontinuous network facilitates efficient Li‐ion conduction, resulting in enhanced cycle stability and rate performance. As a result, the hierarchical 3D electrode allows to achieve high‐energy‐density of flexible LIBs in a pouch‐type cell (438.6 Wh kg−1/20.4 mWh cm−2).
A dendrite‐free and chemically stabilized lithium metal anode is required for extending battery life and for the application of high energy density coupled with various cathode systems. However, ...uneven Li metal growth and the active surface in nature accelerate electrolyte dissipation and surface corrosion, resulting in poor cycle efficiency and various safety issues. Here, the authors suggest a thin artificial interphase using a multifunctional poly(styrene‐b‐butadiene‐b‐styrene) (SBS) copolymer to inhibit the electrochemical/chemical side reaction during cycling. Based on the physical features, hardness, adhesion, and flexibility, the optimized chemical structure of SBS facilitates durable mechanical strength and interphase integrity against repeated Li electrodeposition/dissolution. The effectiveness of the thin polymer film enables high cycle efficiency through the realization of a dendrite‐free structure and a chemo‐resistive surface of Li metal. The versatile anode demonstrates an improvement in the electrochemical properties, paired with diverse cathodes of high‐capacity lithium cobalt oxide (3.5 mAh cm−2) and oxygen for advanced Li metal batteries with high energy density.
A multi‐functional block copolymer, which has a well‐balanced rigid‐soft character in chemical structure, flexibly controls the morphological structure of lithium metal anode as the breathable artificial interphase. This interphase further restrains the shuttle effect and chemical oxidation related to the anode corrosion through the hydrophobic and chemo‐resistive properties for high‐energy‐density and stable lithium metal batteries with diverse cathode materials.
Lithium (Li) metal has long been thought to be an ideal anode material for high‐energy‐density Li metal batteries (LMBs). Nonetheless, a variety of safety risks and short cycle life due to ...uncontrollable Li dendrite growth limit its practical application. Here, a novel polymer‐based 3D host composed of stacked polymer fibers (SPF) is purposefully designed using a simple electrospinning method to achieve dual‐functional properties that endow bottom‐up Li filling and morphologically regulate Li metal deposition over the host structure. As a result, the SPF allows for uniform Li‐ion flux in the electrode, leading to densely packed Li deposition and further stable cycling in conventional carbonate‐based electrolytes. Besides, a full cell paired with LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode results in a high‐energy‐density battery with a low negative/positive capacity ratio and a wide operating temperature range. This study presents a rational design for improving the stability and safety of Li metal anodes in conventional carbonate‐based electrolytes for advanced LMBs.
Stacked polymer fibers with dual‐functional properties are fabricated using a simple electrospinning method, and they serve as an excellent 3D host. The incorporation of two different fibers suppresses lithium dendrites, allowing for uniformly deposited/dissolved Li metal up to 10 mAh cm−2 with densely packed morphology inside the host. The full cell improves cycle stability under a variety of operating conditions.
Aqueous zinc metal batteries (AZMBs) are emerging energy storage systems that are poised to replace conventional lithium‐ion batteries owing to their intrinsic safety, facile manufacturing process, ...economic benefits, and superior ionic conductivity. However, the issues of inferior anode reversibility and dendritic plating during operation remain challenging for the practical use of AZMBs. Herein, a gel electrolyte based on zwitterionic poly(sulfobetaine methacrylate) (poly(SBMA)) dissolved with different concentrations of ZnSO4 is proposed. Two‐dimensional correlation spectroscopy based on Raman analysis reveals an enhanced interaction priority between the polar groups in SBMA and the dissolved ions as electrolyte concentration increases, which establishes a robust interaction and renders homogeneous ion distribution. Attributable to the modified coordination, zwitterionic gel polymer electrolyte with 5 mol kg−1 of ZnSO4 (ZGPE‐5) facilitates stable zinc deposition and improves anode reversibility. By taking advantage of preferential coordination, a symmetrical cell evaluation employing ZGPE‐5 demonstrates a cycle life over 3600 h, where ZGPE‐5 also exerts a beneficial effect on the full cell cycling when assembled with Zn0.25V2O5 cathode. This study elucidates changes in the internal ion behavior that are dependent on electrolyte concentrations and pave the way for durable AZMBs.
A zwitterionic polymer‐based gel electrolyte is proposed for an advanced aqueous zinc metal battery. By controlling the concentration of dissolved salt, electrochemical behaviors can be modified, attributable to the change in the coordination priority order. Accordingly, the interaction between charge carriers and the gel matrix is intensified, which contributes to the improved reversibility of the zinc anode.
Rechargeable batteries have been a profoundly greater part of our lives than we could have ever imagined. The rechargeable Li‐ion batteries (LIBs) that have been developed for transport systems even ...put fossil fuels in the corner. However, state‐of‐the‐art Li‐ion batteries with graphite anodes are now approaching their theoretical specific energy limits, so they cannot meet the increasing demands of a range of portable electronics and large‐scale energy storage systems. Li metal is one of the most promising anode materials that could break through the energy density bottleneck of Li‐ion batteries due to its ultrahigh specific capacity and very low potential compared to other anode materials. Nonetheless, the direct use of Li metal in commercial battery systems has been hindered due to significant obstacles associated with it such as safety issues, corrosion from chemical reactions that occur inside the battery, or poor cycling performance. The fundamental reason for these problems is the dendritic growth of Li‐ions on the Li metal anode during cycling, as a result of the interfacial phenomena of Li metal and electrolytes. Modification of the Li metal interface with an electrolyte presents an efficient solution to solve these problems. In this review, the current challenges facing the development of Li metal anodes are presented in detail. The most recent advances in Li metal anodes using a controlled interface between the Li metal surface and an electrolyte are highlighted and an introduction on the synthesis and production methods for the application of high‐energy‐density battery systems such as Li‐oxygen (Li−O2), Li‐sulfur (Li−S), and Li metal batteries with high‐energy density cathodes is presented. Furthermore, the recent developments in the in situ/operando analysis tools adopted for the investigation of Li metal anodes such as the structural and chemical changes, dynamic properties, and solid–electrolyte interface (SEI) layer properties are described and summarized. Finally, some suggestions are given in the direction of the development of Li metal with artificial surface layers for use in future high‐energy batteries.
Compelling artificial layers: Lithium metal interface modification is one solution to advance commercialization of high‐energy batteries with lithium metal anodes. This Review describes challenges associated with Li metal anodes, summarizes the state‐of‐the‐art artificial layers on lithium metal anodes for realizing high‐energy battery systems, and introduces in situ/ex situ analysis method for lithium metal anodes to figure out complicated mechanisms.
Lithium metal anode (LMA) emerges as a promising candidate for lithium (Li)‐based battery chemistries with high‐energy‐density. However, inhomogeneous charge distribution from the unbalanced ...ion/electron transport causes dendritic Li deposition, leading to “dead Li” and parasitic reactions, particularly at high Li utilization ratios (low negative/positive ratios in full cells). Herein, an innovative LMA structural model deploying a hyperporous/hybrid conductive architecture is proposed on single‐walled carbon nanotube film (HCA/C), fabricated through a nonsolvent induced phase separation process. This design integrates ionic polymers with conductive carbon, offering a substantial improvement over traditional metal current collectors by reducing the weight of LMA and enabling high‐energy‐density batteries. The HCA/C promotes uniform lithium deposition even under rapid charging (up to 5 mA cm−2) owing to its efficient mixed ion/electron conduction pathways. Thus, the HCA/C demonstrates stable cycling for 200 cycles with a low negative/positive ratio of 1.0 when paired with a LiNi0.8Co0.1Mn0.1O2 cathode (areal capacity of 5.0 mAh cm−2). Furthermore, a stacked pouch‐type full cell using HCA/C realizes a high energy density of 344 Wh kg−1cell/951 Wh L−1cell based on the total mass of the cell, exceeding previously reported pouch‐type full cells. This work paves the way for LMA development in high‐energy‐density Li metal batteries.
Lithium metal anode should satisfy significant requirements related to fast‐charging feasibility and high‐energy‐density battery design. The hyperporous/hybrid conductive electrode induces simultaneous lithium deposition and facile lithium densification kinetics at fast current density. Besides, carbon‐based ultra‐light architecture realizes dramatic weight reduction of lithium metal anode, compared with a typical metal current collector to effectively achieve high gravimetric energy density.
Abstract At the forefront of technological advancement, the proliferation of portable and wearable electronics has necessitated the development of innovative power solutions. As these devices become ...increasingly indispensable in daily life, the demand for sustainable and adaptable power sources has intensified. This review focuses on integrated self‐charging power systems (SCPSs), which synergize energy storage systems, particularly through rechargeable batteries like lithium‐ion batteries, with energy harvesting from solar, mechanical, thermal, and chemical energy. These SCPSs extend operational times, reduce recharging frequency, and have the potential to develop self‐sufficient power systems. The study explores various approaches to optimize both individual components and the integrated power system for wearable and flexible electronics, covering SCPSs that combine multiple energy‐harvesting strategies. Special attention is given to design considerations, material advancements, and engineering challenges, alongside the latest research breakthroughs in energy harvesting and storage technology. The review concludes with an assessment of the prospects and challenges in the field of battery‐integrated energy harvesting systems, highlighting the need for advancements in energy density, power output, and safety to meet the demands of modern electronics.
