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Calcium‐ion batteries (CIBs) are considered as promising alternatives in large‐scale energy storage due to their divalent electron redox properties, low cost, and high volumetric/gravimetric capacity. However, the high charge density of Ca2+ contributes to strong electrostatic interaction between divalent Ca2+ and hosting lattice, leading to sluggish kinetics and poor rate performance. Here, in situ formed poly(anthraquinonyl sulfide) (PAQS)@CNT composite is reported as nonaqueous calcium‐ion battery cathode. The enolization redox chemistry of organics has fast redox kinetics, and the introduction of carbon nanotube (CNT) accelerates electron transportation, which contributes to fast ionic diffusion. As the conductivity of the PAQS is enhanced by the increasing content of CNT, the voltage gap is significantly reduced. The PAQS@CNT electrode exhibits specific capacity (116 mAh g−1 at 0.05 A g−1), high rate capacity (60 mAh g−1 at 4 A g−1), and an initial capacity of 82 mAh g−1 at 1 A g−1 (83% capacity retention after 500 cycles). The electrochemical mechanism is proved to be that the PAQS undergoes reduction reaction of their carbonyl bond during discharge and becomes coordinated by Ca2+ and Ca(TFSI)+ species. Computational simulation also suggests that the construction of Ca2+ and Ca(TFSI)+ co‐intercalation in the PAQS is the most reasonable pathway. Poly(anthraquinonyl sulfide)@CNT composite is reported as nonaqueous calcium‐ion battery (CIB) cathode. The introduction of carbon nanotube (CNT) improves conductivity and reaction kinetics of the PAQS. The demonstrated rate performance of PAQS@34%CNT surpasses reported inorganic cathode materials for nonaqueous CIBs. The electrochemical mechanism is proved to be that Ca2+ and Ca(TFSI)+ prefer to co‐intercalate in the PAQS.

The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium‐ion battery. Potassium‐ion batteries (KIBs) are regarded as a kind of promising candidate for large‐scale energy storage owing to the high abundance and low cost of potassium resources. Nevertheless, further development and wide application of KIBs are still challenged by several obstacles, one of which is their fast capacity deterioration at high rates. A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies. This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high‐rate performances for KIBs, and also the beneficial conceptions are consciously extracted from the recent progress. Particularly, basic insights into the recent engineering strategies, structural innovation, and the related advances of carbonaceous anodes for high‐rate KIBs are under specific concerns. Based on the achievements attained so far, a perspective on the foregoing, and proposed possible directions, and avenues for designing high‐rate anodes, are presented finally. The construction of suitable carbonaceous anodes is one of the core technologies to design high‐rate potassium‐ion batteries. Electronic conductivity and ion diffusivity of anodes are two key parameters. To realize a balance between these two parameters, many strategies of framework and morphology design for carbonaceous materials have been proposed. An overview of the design principles and typical advancements are presented in this article. Selected examples and perspectives on designing high‐rate anodes are stated.

The fast charging‐discharging performance of power batteries has very practical significance. In terms of electrochemistry, this requires fast and stable kinetics for electrochemical reaction processes. Despite the great complexity of kinetics, it is clear that lithium‐ion desolvation and a subsequent step of crossing through cathode‐electrolyte interphase (CEI) are crucial to high‐rate performance, in which the two key steps depend heavily on the working electrolyte formula. In this work, a customized electrolyte is developed to coordinate ion desolvation and interphase formation by introducing vinylene carbonate (VC), triphenylboroxin (TPBX), and fluoroethylene carbonate (FEC) but excluding ethylene carbonate (EC). Serving Ni‐rich cathodes, the customized electrolyte generates a double‐layered CEI, LiF‐dominated inorganics inner layer, and ROCOOLi‐dominated organics outer layer, which is not only stable and very efficient for lithium ion transport. Meanwhile, a PF6−${\\mathrm{PF}}_6^ - $‐dominated solvation structure is induced and effectively decreases the desolvation energy to 29.72 kJ mol−1, supporting fast lithium ion transport in the cathode interfacial processes. Consequently, the Ni‐rich lithium‐ion battery achieves a stable long cycle at a superior high rate of 10 C. A customized electrolyte for coordinating ion desolvation and interphase formation of superior high‐rate Ni‐rich lithium batteries is developed. A stable double‐layered CEI is generated, and a PF6−${\\mathrm{PF}}_6^ - $‐dominated solvation structure is induced to effectively decrease the desolvation energy, both of which support fast lithium ion transport in the cathode interfacial processes.

Vanadium redox flow batteries (VRFBs) are receiving increasing interest in energy storage fields because of their safety and versatility. However, the electrocatalytic activity of the electrode is a pivotal factor that still restricts the power and cycling capabilities of VRFBs. Here, a hierarchical carbon micro/nanonetwork (HCN) electrode codoped with nitrogen and phosphorus is prepared for application in VRFBs by cross‐linking polymerization of aniline and physic acid, and subsequent pyrolysis on graphite felt. Due to the hierarchical electron pathways and abundant heteroatom active sites, the HCN exhibits superior electrocatalysis toward the vanadium redox couples and imparts the VRFBs with an outstanding energy efficiency and extraordinary stability after 2000 cycles at 250 mA cm−2 and a discharge capacity of 10.5 mA h mL−1 at an extra‐large current density of 400 mA cm−2. Such a micro/nanostructure design will force the advancement of durable and high‐power VRFBs and other electrochemical energy storage devices. A hierarchical carbon micro/nanonetwork (HCN) with nitrogen and phosphorus codoping is fabricated, which serves as a stable and high‐area structure to homogenize the ion and electron distribution and accelerate vanadium redox reactions with the aid of abundant catalytic sites, exhibiting a high‐rate performance and durable cycle life toward vanadium redox flow battery.

Carbon-coated Li4Ti5O12 (LTO) has been prepared using polyimide (PI) as a carbon source via the thermal imidization of polyamic acid (PAA) followed by a carbonization process. In this study, the PI with different structures based on pyromellitic dianhydride (PMDA), 4,4′-oxydianiline (ODA), and p-phenylenediamine (p-PDA) moieties have been synthesized. The effect of the PI structure on the electrochemical performance of the carbon-coated LTO has been investigated. The results indicate that the molecular arrangement of PI can be improved when the rigid p-PDA units are introduced into the PI backbone. The carbons derived from the p-PDA-based PI show a more regular graphite structure with fewer defects and higher conductivity. As a result, the carbon-coated LTO exhibits a better rate performance with a discharge capacity of 137.5 mAh/g at 20 C, which is almost 1.5 times larger than that of bare LTO (94.4 mAh/g).

The significant demand for energy storage systems has spurred innovative designs and extensive research on lithium‐ion batteries (LIBs). To that end, an in‐depth examination of utilized materials and relevant methods in conjunction with comparing electrochemical mechanisms is required. Lithium titanate (LTO) anode materials have received substantial interest in high‐performance LIBs for numerous applications. Nevertheless, LTO is limited due to capacity fading at high rates, especially in the extended potential range of 0.01–3.00 V versus Li+/Li, while delivering the theoretical capacity of 293 mAh g−1. This study demonstrates how the performance of the LTO anode can be improved by modifying the manufacturing process. Altering the dry and wet mixing duration and speeds throughout the manufacturing process leads to differences in particle sizes and homogeneity of dispersion and structure. The optimized anode at 5 A g−1 (≈17C) and 10 A g−1 (≈34C) yielded 188 and 153 mAh g−1 and retained 73% and 68% of their initial capacity after 1000 cycles, respectively. The following findings offer valuable information regarding the empirical modifications required during electrode fabrication. Additionally, it sheds light on the potential to produce efficient anodes using commercial LTO powder. The article optimizes spinel lithium titanate (LTO) anode preparation for Li‐ion batteries, enhancing high‐rate performance. By adjusting dry and wet mixing times and speeds, the study improves particle size, distribution, and electrochemical performance, resulting in high capacity and stability over many cycles. This offers insights for efficient anode production using commercial LTO powder.

HighlightsHigh-entropy oxides O3-Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2 cathode constructed by compatible radius and different Fermi level ions was designed for solid-state Na-ion batteries.Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2 cathode exhibits high-rate performance, air stability and electrochemically thermal stability.A series of characterizations were performed to explore energy storage mechanism of Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2.Na-ion O3-type layered oxides are prospective cathodes for Na-ion batteries due to high energy density and low-cost. Nevertheless, such cathodes usually suffer from phase transitions, sluggish kinetics and air instability, making it difficult to achieve high performance solid-state sodium-ion batteries. Herein, the high-entropy design and Li doping strategy alleviate lattice stress and enhance ionic conductivity, achieving high-rate performance, air stability and electrochemically thermal stability for Na0.95Li0.06Ni0.25Cu0.05Fe0.15Mn0.49O2. This cathode delivers a high reversible capacity (141 mAh g−1 at 0.2C), excellent rate capability (111 mAh g−1 at 8C, 85 mAh g−1 even at 20C), and long-term stability (over 85% capacity retention after 1000 cycles), which is attributed to a rapid and reversible O3–P3 phase transition in regions of low voltage and suppresses phase transition. Moreover, the compound remains unchanged over seven days and keeps thermal stability until 279 ℃. Remarkably, the polymer solid-state sodium battery assembled by this cathode provides a capacity of 92 mAh g−1 at 5C and keeps retention of 96% after 400 cycles. This strategy inspires more rational designs and could be applied to a series of O3 cathodes to improve the performance of solid-state Na-ion batteries.

Growing market demand from portable electronics to electric automobiles boosts the development of lithium-ion batteries (LIBs) with high energy density and rate performance. However, strong solvation effect between lithium ions (Li + ) and solvent molecules in common electrolytes limits the mobility of Li + ions in electrolytes. Consequently, anions dominate the charge conduction in electrolytes, and in most cases, the value of Li + transference number ( T + ) is between 0.2 and 0.4. A low T + will aggravate concentration polarization in the process of charging and discharging, especially at high rate, which not only increases the overpotential but also intensifies side reactions, along with uneven deposition of lithium (Li) and the growth of lithium dendrites when lithium metal is used as anode. In this review, promising strategies to improve T + in liquid electrolytes would be summarized. The migration of Li + ions is affected directly by the types and concentration of lithium salts, solvents, and additives in bulk electrolytes. Besides, Li + ions will pass through the separator and solid electrolyte interphase (SEI) when transferring between anodes and cathodes. With this in mind, we will classify and summarize threads of enhancing T + from five aspects: lithium salts, solvents, additives, separators, and SEI based on different mechanisms, including covalently bonding, desolvation effect, Lewis acid-base interaction, electrostatic interaction, pore sieving, and supramolecular interaction. We believe this review will present a systematic understanding and summary on T + and point out some feasible threads to enhance battery performance by enhancing T + .

The interlayer modification and the intercalation pseudocapacitance have been combined in vanadium oxide electrode for aqueous zinc‐ion batteries. Intercalation pseudocapacitive hydrated vanadium oxide Mn1.4V10O24·12H2O with defective crystal structure, interlayer water, and large interlayer distance has been prepared by a spontaneous chemical synthesis method. The inserted Mn2+ forms coordination bonds with the oxygen of the host material and strengthens the interaction between the layers, preventing damage to the structure. Combined with the experimental data and DFT calculation, it is found that Mn2+ refines the structure stability, adjusts the electronic structure, and improves the conductivity of hydrated vanadium oxide. Also, Mn2+ changes the migration path of Zn2+, reduces the migration barrier, and improves the rate performance. Therefore, Mn2+‐inserted hydrated vanadium oxide electrode delivers a high specific capacity of 456 mAh g−1 at 0.2 A g–1, 173 mAh g–1 at 40 A g–1, and a capacity retention of 80% over 5000 cycles at 10 A g–1. Furthermore, based on the calculated zinc ion mobility coefficient and Zn(H2O)n2+ diffusion energy barrier, the possible migration behavior of Zn(H2O)n2+ in vanadium oxide electrode has also been speculated, which will provide a new reference for understanding the migration behavior of hydrated zinc‐ion. The strategy of interlayer modification of Mn2+ is applied to regulate the interlayer atomic coordination structure, electronic structure, and affect Zn2+ migration behavior in the vanadium oxide (V10O24·nH2O). Zinc ion intercalation pseudocapacitance, ultra‐high rate performance, and cycling stability are achieved and the Zn(H2O)n2+ migration behavior is analyzed and speculated. ​

HighlightsZero capacity fading after over 3000 cycles at 1 C.Only 6.4% capacity is lost when rate is increased by 50 times.Diffusion mechanism of formation and fracture of hydrogen bonds is proposed.Aqueous ammonium ion batteries are regarded as eco-friendly and sustainable energy storage systems. And applicable host for NH4+ in aqueous solution is always in the process of development. On the basis of density functional theory calculations, the excellent performance of NH4+ insertion in Prussian blue analogues (PBAs) is proposed, especially for copper hexacyanoferrate (CuHCF). In this work, we prove the outstanding cycling and rate performance of CuHCF via electrochemical analyses, delivering no capacity fading during ultra-long cycles of 3000 times and high capacity retention of 93.6% at 50 C. One of main contributions to superior performance from highly reversible redox reaction and structural change is verified during the ammoniation/de-ammoniation progresses. More importantly, we propose the NH4+ diffusion mechanism in CuHCF based on continuous formation and fracture of hydrogen bonds from a joint theoretical and experimental study, which is another essential reason for rapid charge transfer and superior NH4+ storage. Lastly, a full cell by coupling CuHCF cathode and polyaniline anode is constructed to explore the practical application of CuHCF. In brief, the outstanding aqueous NH4+ storage in cubic PBAs creates a blueprint for fast and sustainable energy storage.