Low Interface Energies Tune the Electrochemical Reversibility of Tin Oxide Composite Nanoframes as Lithium-Ion Battery Anodes

Abstract

The conversion reaction of lithia can push up the capacity limit of tin oxide-based anodes. However, the poor reversibility limits the practical applications of lithia in lithium-ion batteries. The latest reports indicate that the reversibility of lithia has been appropriately promoted by compositing tin oxide with transition metals. The underlying mechanism is not revealed. To design better anodes, we studied the nanostructured metal/Li2O interfaces through atomic-scale modeling and proposed a porous nanoframe structure of Mn/Sn binary oxides. The first-principles calculation implied that because of a low interface energy of metal/Li2O, Mn forms smaller particles in lithia than Sn. Ultrafine Mn nanoparticles surround Sn and suppress the coarsening of Sn particles. Such a composite design and the resultant interfaces significantly enhance the reversible Li-ion storage capabilities of tin oxides. The synthesized nanoframes of manganese tin oxides exhibit an initial capacity of 1620.6 mA h g–1 at 0.05 A g–1. Even after 1000 cycles, the nanoframe anode could deliver a capacity of 547.3 mA h g–1 at 2 A g–1. In general, we demonstrated a strategy of nanostructuring interfaces with low interface energy to enhance the Li-ion storage capability of binary tin oxides and revealed the mechanism of property enhancement, which might be applied to analyze other tin oxide composites.

Highly Reversible Lithium Storage of Nitrogen‐Doped Carbon@MnO Hierarchical Hollow Spheres as Advanced Anode Materials

“…[28] Two distinct Mn 2p signals at 653.6 and 641.8 eV can be assigned to Mn2p 1/2 and Mn2p 3/2 , respectively ( Figure 4e). [12,37] Moreover, the aforementioned peaks and their corresponding satellite peaks at 654.7 and 643.2 eV are well consistent with those of MnO in the literatures (Figure 4e). [8] XPS characterization of NC@MnO HHSs confirms that the C 1s spectrum can well fit to six peaks at 284.3, 284.8, 285.5, 286.5, 288.0 and 289.3 eV, which correspond to C=C, CÀ C, CÀ N, CÀ OH, C=O and OÀ C=O components, respectively ( Figure 4f).…”

“…The N‐doping of carbon hollow spheres can form the defect and offer more active sites for the fast Li + absorption and diffusion, resulting in high electrical conductivity and outstanding rate capability . Two distinct Mn 2p signals at 653.6 and 641.8 eV can be assigned to Mn2p 1/2 and Mn2p 3/2 , respectively (Figure e) . Moreover, the aforementioned peaks and their corresponding satellite peaks at 654.7 and 643.2 eV are well consistent with those of MnO in the literatures (Figure e) .…”

“…The capacitive‐controlled contribution (at a fixed potential) is calculated to 57.0 %, 67.7 %, 74.8 % and 80.7 % for NC@MnO HHSs at 0.2, 0.5, 1.0 and 2.0 mVs −1 as illustrated by bar charts (Figure S8c), revealing the gradually enhanced capacitive‐controlled contribution with increasing scan rate. A high percentage of capacitive‐controlled contribution implies that hollow nanocomposites offer rapid kinetics for lithium‐ion storage …”

“…A high percentage of capacitive-controlled contribution implies that hollow nanocomposites offer rapid kinetics for lithium-ion storage. [37] Figure 7 and S9 display SEM and TEM images of NC@MnO HHSs, MnO nanoparticles and NHCSs after 200 cycles, respectively. In Figure 7c-d Figure 7f).…”

Enabling Full Conversion Reaction with High Reversibility to Approach Theoretical Capacity for Sodium Storage

“…The presence of metallic Fe with uniform distribution provides additional fast pathway for electron transport, which could enhance the electron transfer kinetics . Furthermore, previous studies have demonstrated that the coarsening of Sn nanograins could inevitably take place in the mixture of Sn/Na 2 S during the desodiation process, which reduces the reversibility of the sodiation/desodiation reaction for SnS 2 . In this work, the uniformly distributed nanosized Fe grains could act as barriers and effectively hamper the migration of Sn nanograins, thus preventing the coarsening of Sn phase.…”