A Novel High‐Capacity Anode Material Derived from Aromatic Imides for Lithium‐Ion Batteries

A novel anode material for lithium‐ion batteries derived from aromatic imides with multicarbonyl group conjugated with aromatic core structure is reported, benzophenolne‐3,3′,4,4′‐tetracarboxylimide oligomer (BTO). It could deliver a reversible capacity of 829 mA h g^?1 at 42 mA g^?1 for 50 cycles with a stable discharge plateaus ranging from 0.05–0.19 V versus Li⁺/Li. At higher rates of 420 and 840 mA g^?1, it can still exhibit excellent cycling stability with a capacity retention of 88% and 72% after 1000 cycles, delivering capacity of 559 and 224 mA h g^?1. In addition, a rational prediction of the maximum amount of lithium intercalation is proposed and explored its possible lithium storage mechanism.     

Significant Capacity and Cycle‐Life Improvement of Lithium‐Ion Batteries through Ultrathin Conductive Film Stabilized Cathode Particles

Atomic layer deposition (ALD), as a thin film deposition technique, has been explored as a viable path to improve the performance of lithium‐ion batteries. However, a trade‐off between the species transport (capacity) and protection (lifetime), resulting from the insulating properties of ALD films, is the key challenge in ALD technology. Here we report a breakthrough to overcome this trade‐off by coating an ultrathin conformal cerium dioxide (CeO₂) film on the surfaces of LiMn₂O₄ particles. The optimized CeO₂ film (≈3 nm) coated particles exhibit a significant improvement in capacity and cycling performance compared to uncoated (UC), Al₂O₃ coated, and ZrO₂ coated samples at room temperature and 55 °C for long cycling numbers. The initial capacity of the 3 nm CeO₂‐coated sample shows 24% increment compared to the capacity of the uncoated one, and 96% and 95% of the initial capacity is retained after 1000 cycles with 1C rate at room temperature and 55 °C, respectively. The detailed electrochemical data reveal that the suppression of the impedance rise and the facile transport of the species are the main contributors to the success.     

Nano‐Architectured Composite Anode Enabling Long‐Term Cycling Stability for High‐Capacity Lithium‐Ion Batteries

Failure mechanisms associated with silicon‐based anodes are limiting the implementation of high‐capacity lithium‐ion batteries. Understanding the aging mechanism that deteriorates the anode performance and introducing novel‐architectured composites offer new possibilities for improving the functionality of the electrodes. Here, the characterization of nano‐architectured composite anode composed of active amorphous silicon domains (a‐Si, 20 nm) and crystalline iron disilicide (c‐FeSi₂, 5–15 nm) alloyed particles dispersed in a graphite matrix is reported. This unique hierarchical architecture yields long‐term mechanical, structural, and cycling stability. Using advanced electron microscopy techniques, the nanoscale morphology and chemical evolution of the active particles upon lithiation/delithiation are investigated. Due to the volumetric variations of Si during lithiation/delithiation, the morphology of the a‐Si/c‐FeSi₂ alloy evolves from a core‐shell to a tree‐branch type structure, wherein the continuous network of the active a‐Si remains intact yielding capacity retention of 70% after 700 cycles. The root cause of electrode polarization, initial capacity fading, and electrode swelling is discussed and has profound implications for the development of stable lithium‐ion batteries.     

Carbon‐Coated Li3VO4 Spheres as Constituents of an Advanced Anode Material for High‐Rate Long‐Life Lithium‐Ion Batteries

Lithium‐ion batteries are receiving considerable attention for large‐scale energy‐storage systems. However, to date the current cathode/anode system cannot satisfy safety, cost, and performance requirements for such applications. Here, a lithium‐ion full battery based on the combination of a Li₃VO₄ anode with a LiNi_0.5Mn_1.5O₄ cathode is reported, which displays a better performance than existing systems. Carbon‐coated Li₃VO₄ spheres comprising nanoscale carbon‐coating primary particles are synthesized by a morphology‐inheritance route. The observed high capacity combined with excellent sample stability and high rate capability of carbon‐coated Li₃VO₄ spheres is superior to other insertion anode materials. A high‐performance full lithium‐ion battery is fabricated by using the carbon‐coated Li₃VO₄ spheres as the anode and LiNi_0.5Mn_1.5O₄ spheres as the cathode; such a cell shows an estimated practical energy density of 205 W h kg^?1 with greatly improved properties such as pronounced long‐term cyclability, and rapid charge and discharge.     

Flexible 3D Porous MXene Foam for High‐Performance Lithium‐Ion Batteries

2D transition‐metal carbides and nitrides, named MXenes, are promising materials for energy storage, but suffer from aggregation and restacking of the 2D nanosheets, which limits their electrochemical performance. In order to overcome this problem and realize the full potential of MXene nanosheets, a 3D MXene foam with developed porous structure is established via a simple sulfur‐template method, which is freestanding, flexible, and highly conductive, and can be directly used as the electrode in lithium‐ion batteries. The 3D porous architecture of the MXene foam offers massive active sites to enhance the lithium storage capacity. Moreover, its foam structure facilitates electrolyte infiltration for fast Li⁺ transfer. As a result, this flexible 3D porous MXene foam exhibits significantly enhanced capacity of 455.5 mAh g^?1 at 50 mA g^?1, excellent rate performance (101 mAh g^?1 at 18 A g^?1), and superior ultralong‐term cycle stability (220 mAh g^?1 at 1 A g^?1 after 3500 cycles). This work not only demonstrates the great superiority of the 3D porous MXene foam but also proposes the sulfur‐template method for controllable constructing of the 3D foam from 2D nanosheets at a relatively low temperature.     

Nitrogen Doped γ‐Graphyne: A Novel Anode for High‐Capacity Rechargeable Alkali‐Ion Batteries

High energy density is the major demand for next‐generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon–based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ‐graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g^?1) and Na (570.4 mAh g^?1) storage capacities at 100 mA g^?1 and presents excellent rate capabilities (526 mAh g^?1 for LIBs and 180.2 mAh g^?1 for SIBs) at 5 A g^?1. The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (E_b) and adsorption energies (E_ad) of Li/Na atoms in NGY are also studied and imine‐N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first‐principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes.     

Carbon‐Coated Na3.32Fe2.34(P2O7)2 Cathode Material for High‐Rate and Long‐Life Sodium‐Ion Batteries

Rechargeable sodium‐ion batteries are proposed as the most appropriate alternative to lithium batteries due to the fast consumption of the limited lithium resources. Due to their improved safety, polyanion framework compounds have recently gained attention as potential candidates. With the earth‐abundant element Fe being the redox center, the uniform carbon‐coated Na_3.32Fe_2.34(P₂O₇)₂/C composite represents a promising alternative for sodium‐ion batteries. The electrochemical results show that the as‐prepared Na_3.32Fe_2.34(P₂O₇)₂/C composite can deliver capacity of ≈100 mA h g^?1 at 0.1 C (1 C = 120 mA g^?1), with capacity retention of 92.3% at 0.5 C after 300 cycles. After adding fluoroethylene carbonate additive to the electrolyte, 89.6% of the initial capacity is maintained, even after 1100 cycles at 5 C. The electrochemical mechanism is systematically investigated via both in situ synchrotron X‐ray diffraction and density functional theory calculations. The results show that the sodiation and desodiation are single‐phase‐transition processes with two 1D sodium paths, which facilitates fast ionic diffusion. A small volume change, nearly 100% first‐cycle Coulombic efficiency, and a pseudocapacitance contribution are also demonstrated. This research indicates that this new compound could be a potential competitor for other iron‐based cathode electrodes for application in large‐scale Na rechargeable batteries.