Sea Urchin-like Si@MnO2@rGO as Anodes for High-Performance Lithium-Ion Batteries

Enhanced Lithium Storage Performance: Dual-Modified Electrospun Si@MnO@CNFs Composites for Advanced Anodes

Due to its many benefits, including high specific capacity, low voltage plateau, and plentiful supplies, silicon-based anode materials are a strong contender to replace graphite anodes. However, silicon has drawbacks such as poor electrical conductivity, abrupt volume changes during the discharge process, and continuous growth of the solid electrolyte interfacial (SEI) film during cycling, which would cause the electrode capacity to degrade quickly. Coating the silicon's exterior with carbon or metal oxide is a popular method to resolve the above-mentioned problems. In light of those above, the liquid-phase approach and electrostatic spinning technique were used in this work to create Si@MnO@CNFs bilayer-coated silicon-based anode materials. Because of the well-thought-out design, MnO and C bilaterally coat the silicon nanoparticles, significantly reducing their volume effect during cycling. Furthermore, manganese oxide has outstanding electrochemical kinetics and an excellent theoretical capacity. The carbon nanofibers' outermost layer increases the material's conductivity and stabilizes the composite material's structure, reducing the volume effect. After 1100 cycles at 2 A g-1, the composite anode material prepared in this work can still maintain a high capacity of 994.4 mAh g-1. This study offers an unusual combination of silicon and MnO that might set the way for the application of silicon-based composites in lithium-ion batteries.

Binder-Free Intertwined Si and MnO2 Composite Electrode for High-Performance Li-Ion Battery Anode

Silicon is considered as the most felicitous anode material candidate for lithium-ion batteries on account of abundant availability, suitable operating potential, and high specific capacity. Nevertheless, drastic volume expansion during the cycle impedes its practical utilization. Herein, Si and MnO2 (Si-MO) constructed the binder-free intertwined electrode that is reported to effectively improve upon the cycling stability of Si-based materials. The Si-based electrode without a binder has good electrical conductivity, strong adhesion to the substrate, and ample space for mitigating volume expansion. The incorporation of MnO2 establishes a multiphase interface, which mitigates the electrode volume expansion, and supports the electrode structure. Furthermore, MnO2 (∼1230 mAh g-1 theoretical capacity) synergistically enhances the overall capacity of the composite electrodes. Consequently, the Si-MO composite electrode exhibits a reversible specific capacity of 1300 mAh g-1 at 420 mA g-1 and remarkable cycling performance with a specific capacity of 830 mAh g-1 after 500 cycles. In particular, a reversible specific capacity of 837 mAh g-1 at 4200 mA g-1 is achieved and remains stable during 200 cycles. This work provides a potentially feasible way to achieve the Si-based anode commercialization for LIBs.

Nanostructured Electrodes for High-Performance Supercapacitors and Batteries

Emerging renewable energy sources have received extensive attention in the past few decades [...].

Sb Nanoparticles Embedded in the N-Doped Carbon Fibers as Binder-Free Anode for Flexible Li-Ion Batteries

Antimony (Sb) is considered a promising anode for Li-ion batteries (LIBs) because of its high theoretical specific capacity and safe Li-ion insertion potential; however, the LIBs suffer from dramatic volume variation. The volume expansion results in unstable electrode/electrolyte interphase and active material exfoliation during lithiation and delithiation processes. Designing flexible free-standing electrodes can effectively inhibit the exfoliation of the electrode materials from the current collector. However, the generally adopted methods for preparing flexible free-standing electrodes are complex and high cost. To address these issues, we report the synthesis of a unique Sb nanoparticle@N-doped porous carbon fiber structure as a free-standing electrode via an electrospinning method and surface passivation. Such a hierarchical structure possesses a robust framework with rich voids and a stable solid electrolyte interphase (SEI) film, which can well accommodate the mechanical strain and avoid electrode cracks and pulverization during lithiation/delithiation processes. When evaluated as an anode for LIBs, the as-prepared nanoarchitectures exhibited a high initial reversible capacity (675 mAh g^-1) and good cyclability (480 mAh g^-1 after 300 cycles at a current density of 400 mA g^-1), along with a superior rate capability (420 mA h g^-1 at 1 A g^-1). This work could offer a simple, effective, and efficient approach to improve flexible and free-standing alloy-based anode materials for high performance Li-ion batteries.

Strategies for Controlling or Releasing the Influence Due to the Volume Expansion of Silicon inside Si-C Composite Anode for High-Performance Lithium-Ion Batteries

Currently, silicon is considered among the foremost promising anode materials, due to its high capacity, abundant reserves, environmental friendliness, and low working potential. However, the huge volume changes in silicon anode materials can pulverize the material particles and result in the shedding of active materials and the continual rupturing of the solid electrolyte interface film, leading to a short cycle life and rapid capacity decay. Therefore, the practical application of silicon anode materials is hindered. However, carbon recombination may remedy this defect. In silicon/carbon composite anode materials, silicon provides ultra-high capacity, and carbon is used as a buffer, to relieve the volume expansion of silicon; thus, increasing the use of silicon-based anode materials. To ensure the future utilization of silicon as an anode material in lithium-ion batteries, this review considers the dampening effect on the volume expansion of silicon particles by the formation of carbon layers, cavities, and chemical bonds. Silicon-carbon composites are classified herein as coated core-shell structure, hollow core-shell structure, porous structure, and embedded structure. The above structures can adequately accommodate the Si volume expansion, buffer the mechanical stress, and ameliorate the interface/surface stability, with the potential for performance enhancement. Finally, a perspective on future studies on Si-C anodes is suggested. In the future, the rational design of high-capacity Si-C anodes for better lithium-ion batteries will narrow the gap between theoretical research and practical applications.