A Spinel Tin Ferrite with High Lattice-Oxygen Anchored on Graphene-like Porous Carbon Networks for Lithium-Ion Batteries with Super Cycle Stability and Ultra-fast Rate Performances

Abstract

A new type of nano-SnFe2O4 with stable lattice-oxygen and abundant surface defects anchored on ultra-thin graphene-like porous carbon networks (SFO@C) is prepared for the first time by an interesting freezing crystallization salt template method. The functional composite has excellent rate performance and long-term cycle stability for lithium-ion battery (LIB) anodes due to the stable structure, improved conductivity, and shortened migrating distance for lithium-ions, which are derived from the higher lattice-oxygen of SnFe2O4, abundant porous carbon networks and surface defects, and smaller nanoparticles. Under the ultra-high current density of 10, 15, and 20 A g–1 cycling for 1000 times, the SFO@C can provide high reversible capacities of 522.2, 362.5, and 361.1 mAh g–1, respectively. The lithium-ion storage mechanism of the composite was systematically studied for the first time by in situ X-ray diffraction (XRD), ex situ XRD and scanning electron microscopy (SEM), and density functional theory (DFT) calculations. The results indicate that the existence of Li2O and metallic Fe during the lithiation/delithiation process is a key reason for reducing the initial lithium-ion storage reversibility but increasing the rate performance and capacity stability in the subsequent cycles. DFT calculations show that lithium-ions are more easily adsorbed on the (111) crystal plane with a much lower adsorption energy of −7.61 eV than other planes, and the Fe element is the main acceptor of electrons. Moreover, the kinetics investigation indicates that the lithium-ion intercalation and deintercalation in SFO@C are mainly controlled by the pseudocapacitance behavior, which is favorable to enhancing the rate performance. The research provides a new strategy for designing LIB electrode materials with a stable structure and outstanding lithium-ion storage performance.

Synthesis and Investigation of Optical, Magnetic, and Thermoelectric Properties of Li0.5Zr0.5Mg0.5Fe1.5O4Spinel and First-Principles Characterization as an Electrode Material for Li-Ion Batteries

“…The biggest challenges in the field of manufacturing lithium batteries are high-capacity storage, long life, low cost, safety, and fast charge capability. Thanks to their low cost, high abundance, low toxicity, and essentially the structural flexibility of spinel ferrite [e.g., hematite (α-Fe 2 O 3 ) and ′α-LiFe 5 O 8 and their derivatives], there has been significant interest in these materials as electrode materials for lithium-ion batteries. − The presence of vacant interstitials (16c,8b, and 48f) in the spinel structure allows us to use them as additional storage sites; therefore, eight lithium cations can be inserted per unit of formula. , Several studies reveal that magnetite has a theoretical capacity of 926 mAh/g and zinc ferrite (ZnFe 2 O 4 ) can reach 1000 mAh/g . Nonetheless, the compact inverse spinel crystal structure can result in solid-state mass transfer resistances, which may prevent the attainment of the theoretical capacity at nominal rates .…”