Carbon nanotubes coupled with layered graphite to support SnTe nanodots as high-rate and ultra-stable lithium-ion battery anodes

Rational Design of Multinary Metal Chalcogenide Bi0.4 Sb1.6 Te3 Nanocrystals for Efficient Potassium Storage

Multinary metal chalcogenides hold considerable promise for high-energy potassium storage due to their numerous redox reactions. However, challenges arise from issues such as volume expansion and sluggish kinetics. Here, a design featuring a layered ternary Bi0.4 Sb1.6 Te3 anchored on graphene layers as a composite anode, where Bi atoms act as a lattice softening agent on Sb, is presented. Benefiting from the lattice arrangement in Bi0.4 Sb1.6 Te3 and structure, Bi0.4 Sb1.6 Te3 /graphene exhibits a mitigated expansion of 28% during the potassiation/depotassiation process and demonstrates facile K+ ion transfer kinetics, enabling long-term durability of 500 cycles at various high rates. Operando synchrotron diffraction patterns and spectroscopies including in situ Raman, ex situ adsorption, and X-ray photoelectron reveal multiple conversion and alloying/dealloying reactions for potassium storage at the atomic level. In addition, both theoretical calculations and electrochemical examinations elucidate the K+ migration pathways and indicate a reduction in energy barriers within Bi0.4 Sb1.6 Te3 /graphene, thereby suggesting enhanced diffusion kinetics for K+ . These findings provide insight in the design of durable high-energy multinary tellurides for potassium storage.

Recent Advances in Carbon-Based Electrodes for Energy Storage and Conversion

Carbon-based nanomaterials, including graphene, fullerenes, and carbon nanotubes, are attracting significant attention as promising materials for next-generation energy storage and conversion applications. They possess unique physicochemical properties, such as structural stability and flexibility, high porosity, and tunable physicochemical features, which render them well suited in these hot research fields. Technological advances at atomic and electronic levels are crucial for developing more efficient and durable devices. This comprehensive review provides a state-of-the-art overview of these advanced carbon-based nanomaterials for various energy storage and conversion applications, focusing on supercapacitors, lithium as well as sodium-ion batteries, and hydrogen evolution reactions. Particular emphasis is placed on the strategies employed to enhance performance through nonmetallic elemental doping of N, B, S, and P in either individual doping or codoping, as well as structural modifications such as the creation of defect sites, edge functionalization, and inter-layer distance manipulation, aiming to provide the general guidelines for designing these devices by the above approaches to achieve optimal performance. Furthermore, this review delves into the challenges and future prospects for the advancement of carbon-based electrodes in energy storage and conversion.

Progressive Damage Analysis for Spherical Electrode Particles with Different Protective Structures for a Lithium-Ion Battery

Charge-discharge in a lithium-ion battery may produce electrochemical adverse reactions in electrodes as well as electrolytes and induce local inhomogeneous deformation and even mechanical fracture. An electrode may be a solid core-shell structure, hollow core-shell structure, or multilayer structure and should maintain good performance in lithium-ion transport and structural stability in charge-discharge cycles. However, the balance between lithium-ion transport and fracture prevention in charge-discharge cycles is still an open issue. This study proposes a novel binding protective structure for lithium-ion battery and compares its performance during charge-discharge cycles with unprotective structure, core-shell structure and hollow structure. First, both solid and hollow core-shell structures are reviewed, and their analytical solutions of radial and hoop stresses are derived. Then, a novel binding protective structure is proposed to well-balance lithium-ionic permeability and structural stability. Third, the pros and cons of the performance at the outer structure are investigated. Both analytical and numerical results show that the binding protective structure serves with great fracture-proof effectiveness and high lithium-ion diffusion rate. It has better ion permeability than solid core-shell structure but worse structural stability than shell structure. A stress surge is observed at the binding interface with an order of magnitude usually higher than that of the core-shell structure. The radial tensile stress at interface may more easily induce interfacial debonding than superficial fracture.

Patterning Design of Electrode to Improve the Interfacial Stability and Rate Capability for Fast Rechargeable Solid-State Lithium-Ion Batteries

Patterned electrodes were developed for use in solid-state lithium-ion batteries, with the ultimate goal to promote fast-charging attributes through improving electrochemically activated surfaces within electrodes. By a conventional photolithography, patterned arrays of SnO₂ nanowires were fabricated directly on the current collector, and empty channel structures formed between the resulting arrays were customized through modifying the size and interval of the SnO₂ patterns. The composite electrolyte comprising Li₇La₃Zr₂O₁₂ and poly(ethylene oxide) was exploited to secure intimate interfacial contact at the electrode/electrolyte junction while preserving ionic conductivity in the bulk electrolyte. The potential and limitation of the electrode patterning approach were then explored experimentally. For example, the electrochemical behaviors of patterned electrodes were investigated as a function of variations in microchannel structures, and compared with those of conventional film-type electrodes. The findings show promise to improve electrode dynamics when electrochemical reaction kinetics could be hindered by poor interfacial characteristics on electrodes.

The multicomponent synergistic effect of a hierarchical Li0.485La0.505TiO3 solid-state electrolyte for dendrite-free lithium-metal batteries

Development of a composite electrolyte with high ionic conductivity, excellent electrochemical stability and preeminent mechanical strength is beneficial for suppressing Li-dendrite penetration and unstable interfacial reactions in solid-state Li-metal batteries. Herein, a novel composite electrolyte material comprising perovskite Li_0.485La_0.505TiO₃ (LLTO), poly(ethylene oxide) (PEO), and a barium titanate (BTO)-polyimide (PI) composite matrix has been successfully fabricated. Benefiting from the well-defined ion channels, the resulting BTO-PI@LLTO-PEO-FEC-LiTFSI (BP@LPFL) exhibits excellent cycling stability, low interfacial resistance, enhanced mechanical strength, and high ionic conductivity. Particularly, BP@LPFL possesses an excellent ionic conductivity of 3.0 × 10^-4 S cm^-1 at room temperature and achieves a wide electrochemical window of 5.2 V (vs. Li⁺/Li). For Li-LiFePO₄ batteries, such an ingenious structure yields a discharge capacity of 124 mA h g^-1 at 0.1 C after 200 cycles at room temperature and delivers a discharge capacity of 165 mA h g^-1 at 0.1 C after 110 cycles at 60 °C. Additionally, the symmetric Li cell remains stable after 700 h at a current density of 0.5 mA cm^-2. Furthermore, ex situ X-ray photoelectron spectroscopy and ex situ scanning electron microscopy were used to verify the interface evolution. Besides, a flexible full battery is fabricated, which exhibits impressive performance. These properties presented here provide support for BP@LPFL as a feasible candidate electrolyte for solid-state lithium batteries.

Enhanced Structural Stability and Volumetric Capacity of a 3D Pyknotic Graphene Conductive Network via a Pillar Effect of Sn Nanoparticles for Sodium-Ion Batteries

High volumetric capacity and durability anode materials for sodium ion batteries have been urgently required for practical applications. Herein, we reported a Sn-pillared pyknotic graphene conductive network with high-level N-doping. This densely stacked block offers high volumetric Na-ion storage capacity, rapid electrochemical reaction kinetics, and robust structural stability during cycling owing to the high capacity component (metallic Sn ≈847 mAh g^-1), high tap density (≈2.63 g cm^-3), high conductivity (N doping ≈5 at. %), and strong spatially confined and pillared structure. Moreover, theoretical simulations have indicated that the charge accumulation around the N-doped region is more pronounced compared to the pristine one, and electrons accumulate around the N atom while loss occurs at the Na atom. These studies also suggest that it might possibly contribute to higher conductivity and stronger electrophilic reactivity, thereby resulting in enhanced Na-ion storage performance. As a result, the as-obtained electrode material exhibits competitive volumetric capacity (1462 mAh cm^-3 at 0.1 A g^-1), cycling performance (1207 mAh cm^-3 after 100 cycles), and promising rate behavior simultaneously.

Flexible SnTe/carbon nanofiber membrane as a free-standing anode for high-performance lithium-ion and sodium-ion batteries

Flexible electrode plays a key role in flexible energy storage devices. The SnTe/C nanofibers membrane (SnTe/CNFM) with excellent mechanical flexibility has been successfully synthesized for the first time through electrospinning, and it demonstrates outstanding electrochemical performance as free-standing anode for lithium/sodium-ion batteries. The SnTe/CNFM electrode delivers a discharge capacity of 526.7 mAh g^-1 at 1000 mA g^-1 after 1000 cycles in lithium-ion half-cells and a discharge capacity of 236.5 mAh g^-1 at 500 mA g^-1 after 80 cycles in lithium-ion full-cells with a LiFePO₄ cathode. Not only that, it shows a discharge capacity of 182.7 mAh g^-1 at 200 mA g^-1 after 200 cycles in sodium-ion half-cells and a high discharge capacity of 207.0 mAh g^-1 at 500 mA g^-1 after 50 cycles in sodium-ion full-cells with a Na_0.44MnO₂ cathode. Moreover, the prepared SnTe/CNFM exhibits good mechanical flexibility. The SnTe/CNFM can still return to its original state without any breakage after bending, curling, folding and kneading. These results indicate that SnTe/CNFM is expected to become one of the promising free-standing anodes for lithium/sodium-ion batteries.