Electrochemical Performance of Li 4 Ti 5 O 12 Nanowire/Fe 3 O 4 Nanoparticle Compound as Anode Material of Lithium Ion Batteries

A Porous Mooncake-Shaped Li4 Ti5 O12 Anode Material Modified by SmF3 and Its Electrochemical Performance in Lithium Ion Batteries

Reasonably designing and synthesizing advanced electrode materials is significant to enhance the electrochemical performance of lithium ion batteries (LIBs). Herein, a metal-organic framework (MOF, Mil-125) was used as a precursor and template to successfully synthesize the porous mooncake-shaped Li₄ Ti₅ O₁₂ (LTO) anode material assembled from nanoparticles. Even more critical, SmF₃ was used to modify the prepared porous mooncake-shaped LTO material. The SmF₃ -modified LTO maintained a porous mooncake-shaped structure with a large specific surface area, and the SmF₃ nanoparticles were observed to be attach on the surface of the LTO material. It has been proven that the SmF₃ modification can further facilitate the transition from Ti⁴⁺ to Ti³⁺ , reduce the polarization of electrode, decrease charge transfer impedance (R_ct ) and solid electrolyte interface impedance (R_sei ), and increase the lithium ion diffusion coefficient (D_Li ), thereby enhancing the electrochemical performance of LTO. Therefore, the porous mooncake-shaped LTO modified using 2 wt % SmF₃ displays a large specific discharge capacity of 143.8 mAh g^-1 with an increment of 79.16 % compared to pure LTO at a high rate of 10 C (1 C=170 mAh g^-1 ), and shows a high retention rate of 96.4 % after 500 cycles at 5 C-rate.

Porous CaFe2O4 as a promising lithium ion battery anode: a trade-off between high capacity and long-term stability

Metal oxides are considered as attractive candidates as anode materials for lithium ion batteries (LIBs) due to their high capacities compared to commercialized graphite. However, fast capacity fading, which is caused by inherent large volume expansions and agglomeration of active particles upon cycling, is a great challenge. Herein, we propose the design of porous CaFe2O4 electrode material to address the above issue. Compared to pristine iron oxides, CaFe2O4 exhibits a distinct trade-off in terms of high capacity and long-term stability, which is beneficial to the potential practical applications. Such a trade-off effect is attributed to the synergistic effect between the porous structure and the in situ formed CaO nanograins during charging/discharging processes. This work provides an effective strategy in achieving anode materials with high capacity and long-term stability for next-generation LIBs.