The impending energy crisis entails sustainable battery technologies with improved energy density, reliability, safety and lifetime. Hence, it is essential to gain detailed insights into the surface reactions, ionic diffusion, structural and morphological evolution, and degradation mechanisms of battery electrodes. Recently, X-ray techniques emerged as revolutionary tools to reveal an in-depth understanding of the battery during operations. This review provides an overview of the use of in situ/operando X-ray techniques to understand the different functionalities of electrode materials inside the battery. It will focus on the phase transformation, structural evolution and dynamic properties of the battery electrodes, and discuss the relationship between battery failure and electro-chemo-mechanical failure in the electrode. Finally, the limitations of these methods are also discussed with the prospects for effective use of these techniques in the development of advanced battery technologies.
Sodium-metal batteries (SMBs) are considered a promising alternative to lithium-metal batteries due to their high-energy density, low cost, and good low-temperature performance. However, the serious side reactions and dendrites growth during the process of sodium ions deposition/stripping are the bottleneck that inhibits the further capitalization of SMBs, especially at low temperatures. Herein, a porous framework of 50 µm thickness composite gel-polymer-electrolyte (GPE) supported by polyvinylidene difluoride nanowires membrane and Na3Zr2Si2PO12 ceramic particles is proposed to tackle the issues. This GPE not only has high ionic conductivity but also can promote the uniform transportation of sodium ions to form a stable and dense metal-GPE interfacial layer, which can effectively inhibit the side reactions and dendrites growth in a wide temperature range. The assembled Na//GPE//Na3V2(PO4)3 full battery provides a specific capacity of 100 mAh g-1 at 10 C for more than 3000 cycles calendar life at room temperature. Moreover, the full battery based on this GPE has an extraordinary performance at low temperatures, reaching a specific capacity of 93 and 61 mAh g-1 at 0.5 and 1 C at −20°C, respectively. This work provides a reliable solution for low-temperature applications of high-energy density and long-cycle life SMBs.
The aqueous metal–H2O2 batteries have been paid rapidly increasing attention due to their large theoretical energy densities, attractive power density, and multiple applications (air, land, and sea), especially in low-content oxygen or nonoxygen conditions in which metal–air cells are out of work. However, the requirements of metal–H2O2 batteries are different due to the order of metal activities (Mg > Al > Zn) as well as metal–air cells. Aqueous metal–H2O2 batteries mainly include Al–H2O2, Mg–H2O2, and Zn–H2O2 batteries with the respective scientific problems, including battery structures, single/dualelectrolyte systems, electrocatalysts for O2 reduction/evolution reactions, H2O2 reduction/production/decomposition, and the designability of anode to inhibit self-corrosion. In this review, we summarized battery architectures, possible mechanisms, and recent progress in metal–H2O2 batteries, including Al–H2O2, Mg–H2O2, and Zn–H2O2 batteries. Several perspectives are also provided for these research fields, which may be focused on in the future.
Rechargeable lithium-metal batteries (LMBs) hold great promise for providing high-energy density. However, their widespread commercial adoption has been inhibited by critical challenges, for example, the capacity fading from irreversible processes at electrolyte/electrode interfaces and safety concerns originating from the inhomogeneous lithium deposition. Polymer electrolytes benefiting from enhanced electrolyte/electrode contact and low interfacial impedance provide a variable solution to address these challenges and enable a high-energy and flexible battery system. Although promising, inefficient bulky ionic conductivity and poor mechanical stability confront the stable operation of polymer electrolytes in tangible batteries, which highly requires the development of innovative polymer electrolyte chemistries. Among various polymer materials, microporous polymers stand out due to their abundant porosity and customizable micropore structure, positioning them as promising candidates for next-generation electrolyte membranes. This review, therefore, summarizes recent advances in electrolyte membranes based on two new chemistries, hypercrosslinked polymers (HCPs) and porous coordination polymers (PCPs). Other microporous polymers, such as covalent organic polymers, porous organic cages, and polymers of intrinsic microporosity, are also discussed with an emphasis on their applications in LMBs. Most importantly, by reviewing the design strategies, synthesis protocols, and performance in LMBs, we gain insights into the design principles of highperformance electrolyte membranes based on HCPs and PCPs and highlight potential future research directions.
As demand for extended range in electric vehicles and longer battery lifetimes in consumer electronics has grown, so have the requirements for higher energy densities and longer cycle lifetimes of the cells that power them. One solution to this is the implementation of an “anode-free” battery. By removing the anode and plating lithium directly onto the current collector, it is possible to access the same capacities and voltage windows as traditional lithium metal batteries, with the entirety of the lithium source coming from the cathode. Herein, a copper foil current collector coated with niobium oxide or lithium niobium oxide through atomic layer deposition (ALD) is applied to extend the cycling life of the anode-free batteries by reducing dendrite formation and improving the stability of the lithium metal surface throughout cycling. The ALD coatings are able to extend the cycle lifetime in full coin cells from 20 cycles to 80% capacity retained in the bare copper controls to 50 and 115 cycles for the NbO and LiNbO coatings, respectively. Over the lifetime of the cells, the ALD-LiNbO is able to cumulatively offer a staggering improvement of an additional 100 kWh L−1 compared to the bare copper control.
Bismuth trioxide (BT) is considered a fascinating anode material for hybrid supercapacitors (HSCs) due to its high theoretical capacity, but the low conductivity limits further applications. With this in mind, Ce-doped Bi2O3 (Ce-BT) nanoflower spheres were synthesized by a facile and rapid microwave-assisted solvothermal method for HSCs anode materials. It is found that the morphology of BT could be controlled by Ce doping from stacked nanosheets to well-dispersed nanoflowers spheres and producing abundant amorphous regions, thus expediting the ion transport rate. Consequently, when the added Bi to Ce molar ratio is 40:1 (Ce-BT-40), it exhibited a specific capacity of 220 mAh g-1 at 0.5 A g-1. Additionally, when fabricating HSCs with as-prepared Ce-BT-40 and CeNiCo-LDH, an energy density of 59.1 Wh kg-1 is provided at a power density of 652Wkg-1. This work not only reveals the mechanism of the effect of Ce doping on the electrochemical properties of BTs, but also proposes a rapid synthesis method of Ce-BTs by microwave-assisted solvent method, which provides new insights for building advanced HSCs with high energy density and low cost.
Despite their great promise as high-energy-density alternatives to Li-ion batteries, the extensive use of lithium-oxygen (Li-O2) batteries is constrained by the slow kinetics of both the oxygen evolution reaction and oxygen reduction reaction. To increase the overall performance of Li-O2 batteries, it is essential to increase the efficiency of oxygen electrode reactions by constructing effective electrocatalysts. As a high-efficiency catalyst for Li-O2 batteries, high entropy perovskite oxide (La0.8Sr0.2)(Mn0.2Fe0.2Cr0.2Co0.2Ni0.2)O3 (referred to as LS (MFCCN)O3) is designed and investigated in this article. The introduction of dissimilar metals in LS(MFCCN)O3 has the potential to cause lattice deformation, thereby enhancing electron transfer between transition metal ions and facilitating the formation of numerous oxygen vacancies. This feature is advantageous for the reversible production and breakdown of discharge product Li2O2. Consequently, the Li-O2 battery utilizing LS(MFCCN)O3 as a catalyst achieves an impressive discharge capacity of 17,078.2mAh g−1 and exhibits an extended cycling life of 435 cycles. This study offers a useful method for adjusting the catalytic performance of perovskite oxides toward oxygen redox reactions in Li-O2 batteries.
Layered oxides are successful cathode materials for sodium-ion batteries. Many of these oxides show interesting kinetic behavior but have poor structural stability. To overcome this limitation, an alternative material containing potassium in the interlayer space in trigonal prismatic coordination is studied here. The transition-metal layers are formed by sustainable transition elements such as iron and manganese. The solid was prepared using a sol-gel procedure that led to a product with relatively high purity, with a P’3-type structure indexable in the C2/m space group of the monoclinic system. Its electrochemical behavior was studied in sodium metal half-cells. When the cell is charged up to 4.3 V, it is observed that the potassium extraction is not complete. The subsequent discharge of the cell is associated with the intercalation of sodium from the electrolyte. Thus, it is possible to incorporate a greater number of alkaline ions than those extracted in the previous charge. The residual potassium in the structure was found to be favorable to maintaining the structural integrity of the compound upon cycling. This can be explained by the beneficial effect of potassium, which would act as a structural “pillar” in the interlayer, which would reduce structural degradation during cycling.
Wearable electronics are expected to be light, durable, flexible, and comfortable. Many fibrous, planar, and tridimensional structures have been designed to realize flexible devices that can sustain geometrical deformations, such as bending, twisting, folding, and stretching normally under the premise of relatively good electrochemical performance and mechanical stability. As a flexible electrode for batteries or other devices, it possesses favorable mechanical strength and large specific capacity and preserves efficient ionic and electronic conductivity with a certain shape, structure, and function. To fulfill flexible energy-storage devices, much effort has been devoted to the design of structures and materials with mechanical characteristics. This review attempts to critically review the state of the art with respect to materials of electrodes and electrolyte, the device structure, and the corresponding fabrication techniques as well as applications of the flexible energy storage devices. Finally, the limitations of materials and preparation methods, the functions, and the working conditions of devices in the future were discussed and presented.
Aqueous zinc-based batteries (AZBs) with the advantages of high safety, low cost, and satisfactory energy density are regarded as one of the most promising candidates for future energy storage systems. Rampant dendrite growth and severe side reactions that occur at the Zn anode hinder its further development. Recently, a growing number of studies have demonstrated that side reactions are closely related to the active water molecules belonging to the Zn2+ solvated structure in the electrolyte, and reducing the occurrence of side reactions by regulating the relationship between the above two has proven to be a reliable pathway. Nevertheless, a systematic summary of the intrinsic mechanisms and practical applications of the route is lacking. This review presents a detailed description of the close connection between H2O and side reactions at Zn anodes and gives a comprehensive review of experimental strategies to inhibit side reactions by modulating the relationship between Zn2+ and H2O, including anode interface engineering and electrolyte engineering. In addition, further implementation of the above strategies and the modification means for future Zn anodes are discussed.