Hybrid porous bamboo-like CNTs embedding ultrasmall LiCrTiO4 nanoparticles as high rate and long life anode materials for lithium ion batteries

High Pressure Rapid Synthesis of LiCrTiO4 with Oxygen Vacancy for High Rate Lithium-Ion Battery Anodes

Lithium-ion battery based on LiCrTiO₄ (LCTO) is considered to be a promising anode material, as they provide higher safety and durability beyond than that of graphite electrode. However, the applications of this transformative technology demand improved inherent electrical conductivity of LCTO as well as a simple and rapid synthetic route. Here, LCTO with oxygen vacancies (OVs) is fabricated using high-pressure synthesis technology in only 40 min. The optimal synthesis pressure is 0.8 GPa (LCTO-0.8). The reversible capacity of LCTO-0.8 at 1C is 131 mA h g^-1 after 1000 cycles and the capacity retention is nearly 97%, and the reversible capacity of LCTO synthesized at atmospheric pressure (LCTO-P) is 85 mA h g^-1 under the same circumstances. Even at 5C, the reversible capacity is 110 mA h g^-1 , which is 77% higher than LCTO-P. Furthermore, it is confirmed by theoretical calculations that the introduction of OVs has the occupation of electronic states at the Fermi level, which greatly enhances the intrinsic conductivity of LCTO. Specifically, the electronic conductivity has increased by two orders of magnitude compared with LCTO-P. Therefore, high-pressure synthesis technology endows LCTO with superior characteristics, providing a new avenue for industrialization.

Electrochemical Oscillation during Galvanostatic Charging of LiCrTiO4 in Li-Ion Batteries

In the late 1960s, the establishment of Prigogine’s dissipative structure theory laid the foundation for the (electro)chemical oscillation phenomenon, which has been widely investigated in some electrochemical reactions, such as electro-catalysis and electro-deposition, while the electrochemical oscillation of Li-ion batteries has just been discovered in spinel Li₄Ti₅O₁₂ a few years before. In this work, spinel LiCrTiO₄ samples were synthesized by using a high-temperature solid-state method, characterized with SEM (Scanning electron microscope), XRD (X-ray diffraction), Raman and XPS (X-ray photoelectron spectroscopy) measurements, and electrochemically tested in Li-ion batteries to study the electrochemical oscillation. When sintering in a powder form at a temperature between 800 and 900 °C, we achieved the electrochemical oscillation of spinel LiCrTiO₄ during charging, and it is suppressed in the non-stoichiometric LiCrTiO₄ samples, especially for reducing the Li content or increasing the Cr content. Therefore, this work developed another two-phase material as the powder-sintered LiCrTiO₄ exhibiting the electrochemical oscillation in Li-ion batteries, which would inspire us to explore more two-phase electrode materials in Li-ion batteries, Na-ion batteries, etc.

Rational design of FeTiO3/C hybrid nanotubes: promising lithium ion anode with enhanced capacity and cycling performance

Ilmenite FeTiO3 has the advantage of high theoretical capacity and abundant sources as an anode material for lithium-ion batteries (LIBs). However, it suffers inferior rate capability caused by the aggregation of particles. To solve this problem, FeTiO3 nanoparticles embedded in porous CNTs were developed by the sol-gel route and subsequent calcination. The unique hybrids have a uniform distribution of FeTiO3 nanoparticles (5-20 nm) in the carbon matrix. Electrochemical tests prove that the porous FeTiO3/C hybrid nanotubes deliver a high capacity of 612.5 mA h g-1 at 0.2 A g-1 after 300 cycles. Moreover, they present remarkable rate capability and exceptional cycling stability, possessing 163.8 mA h g-1 at 5 A g-1 for 1000 cycles. The enhanced electrochemical performance of the FeTiO3/C hybrid is derived from the shortened Li+ transport length, good structure stability and conductive carbon matrix, which simultaneously solves the major problems of pulverization and agglomeration of FeTiO3 nanoparticles during cycling.

Construction of the NaTi2(PO4)3/C electrode with a one-dimensional porous hybrid structure as an advanced anode for sodium-ion batteries

The inferior electronic conductivity of NASICON materials leads to poor cyclability and rate capability, which severely inhibits their extensive development. Therefore, we have developed a one-dimensional (1D) hybrid electrode material that combines small NaTi2(PO4)3 nanoparticles (5-50 nm) with a porous carbon matrix using a controllable sol-gel strategy. This unique design enables the electrode to possess good structural stability, superior charge transfer kinetics, and low polarization. The intimate combination between the nanoparticles and the porous carbon matrix can effectively facilitate Na+/e- transfer and accommodate volume variation during cycling. The construction of the new structure presented in this work will extend the applications of the NaTi2(PO4)3 system. Furthermore, the formed hybrid structure has potential to be a universal model for various electrode materials.

Li(Na)2FeSiO4/C hybrid nanotubes: promising anode materials for lithium/sodium ion batteries

Porous Li(Na)₂FeSiO₄/C hybrid nanotubes were successfully synthesized by a modified sol–gel strategy and a subsequent calcination process. These nanohybrids exhibited excellent electrochemical performances as anodes for lithium/sodium ion batteries.

Controllable synthesis of peapod-like TiO2@GO@C electrospun nanofiber membranes with enhanced mechanical properties and photocatalytic degradation abilities towards methylene blue

Electrospun peapod-like TiO₂@GO@C nanofiber membranes enhance their photocatalytic properties for the improved crystallinity of TiO₂ and carrier transport, and simultaneously improve their mechanical properties.

Pseudocapacitive Behaviors of Li2FeTiO4/C Hybrid Porous Nanotubes for Novel Lithium-Ion Battery Anodes with Superior Performances

Hybrid nanotubes of cation disordered rock salt structured Li₂FeTiO₄ nanoparticles embedded in porous CNTs were developed. Such unique hybrids with continuous 3D electron transportation paths and isolated small particles have been shown to be an ideal architecture that brought out enhanced electrochemical performances. Meanwhile, they exhibited improved extrinsic capacitive characteristics. In addition, we demonstrate a successful example to use cathode active material as anode for lithium-ion batteries (LIBs). More importantly, our hybrids had much superior electrochemical performances than most of the reported Li₄Ti₅O₁₂-based nanocomposites. Therefore, it is concluded that Li₂FeTiO₄ can be a prospective anode material for LIBs.

Confined formation of monoclinic Na4Ti5O12 nanoparticles embedded into porous CNTs: towards enhanced electrochemical performances for sodium ion batteries

The nanohybrids of monoclinic Na₄Ti₅O₁₂ nanoparticles embedded in porous CNTs show excellent rate performance and cycling stability as an anode for sodium ion batteries.

One-dimensional controllable crosslinked polymers grafted with N-methyl-d-glucamine for effective boron adsorption

Modified one-dimensional crosslinked polymers exhibit good adsorption performances for boron, and magnetic separation is realized by doping Fe₃O₄ nanoparticles.