Search Results (3)

Alloying-type anode materials have considerably promoted the development of potassium-ion batteries (PIBs) and sodium-ion batteries (SIBs), enabling them to achieve high-energy-density. However, large volume expansion and sluggish dynamic behavior have become key issues affecting electrochemical performance. Herein, bismuth (Bi) nano-rods are anchored on reduced graphene (rGO) and encapsulated via N-doped C (NC) to construct Bi@rGO@NC architecture as anode materials for SIBs and PIBs. The hierarchical confinement effect of three-dimensional conductive networks can not only improve electrode stability upon cycling via suppressing the large volume variation, but also eliminate the band gap of Bi and accelerate ion diffusion, thereby exhibiting favorable electrochemical reaction kinetics. Thus, Bi@rGO@NC contributes an ultra-long lifetime, over 1000 cycles, and an outstanding rate property to SIBs and PIBs. This work can pave the way for the construction of high-performance alloying-type anode materials for SIBs and PIBs. Full article

As a promising energy storage system, sodium-ion batteries face challenges related to the stability and high-rate capability of their electrode materials, especially carbon, which is the most studied anode. Previous studies have demonstrated that three-dimensional architectures composed of porous carbon materials with high electrical conductivity have the potential to enhance the storage performance of sodium-ion batteries. Here, high-level N/O heteroatoms-doped carbonaceous flowers with hierarchical pore architecture are synthesized through the direct pyrolysis of homemade bipyridine-coordinated polymers. The carbonaceous flowers could provide effective transport pathways for electrons/ions, thus allowing for extraordinary storage properties in sodium-ion batteries. As a consequence, sodium-ion battery anodes made of carbonaceous flowers exhibit outstanding electrochemical features, such as high reversible capacity (329 mAh g⁻¹ at 30 mA g⁻¹), superior rate capability (94 mAh g⁻¹ at 5000 mA g⁻¹), and ultralong cycle lifetimes (capacity retention rate of 89.4% after 1300 cycles at 200 mA g⁻¹). To better investigate the sodium insertion/extraction-related electrochemical processes, the cycled anodes are experimentally analyzed with scanning electron microscopy and transmission electron microscopy. The feasibility of the carbonaceous flowers as anode materials was further investigated using a commercial Na₃V₂(PO₄)₃ cathode for sodium-ion full batteries. All these findings indicate that carbonaceous flowers may possess great potential as advanced materials for next-generation energy storage applications. Full article

Solid electrolyte interphase (SEI) on a Li anode is critical to the interface stability and cycle life of Li metal batteries. On the one hand, components of SEI with the passivation effect can effectively hinder the interfacial side reactions to promote long-term cycling stability. On the other hand, SEI species that exhibit the active site effect can reduce the Li nucleation barrier and guide Li deposition homogeneously. However, strategies that only focus on a separated effect make it difficult to realize an ideal overall performance of a Li anode. Herein, a dual functional artificial SEI layer simultaneously combining the passivation effect and the active site effect is proposed and constructed via a facial surface chemistry method. Simultaneously, the formed LiF component effectively passivates the anode/electrolyte interface and contributes to the long-term stable cycling performance, while the Li-Mg solid solution alloy with the active site effect promotes the transmission of Li⁺ and guides homogeneous Li deposition with a low energy barrier. Benefiting from these advantages, the Li||Li cell with the modified anode performs with a lower nucleation overpotential of 2.3 mV, and an ultralong cycling lifetime of over 2000 h at the current density of 1 mA cm⁻², while the Li||LiFePO₄ full battery maintains a capacity retention of 84.6% at rate of 1 C after 300 cycles. Full article