Tin Intercalated Ultrathin MoO₃ Nanoribbons for Advanced Lithium–Sulfur Batteries

Abstract

batteries is greatly limited by the highly insulating nature of S 8 /Li 2 S 2-x (x ≤ 1) and the dissolution of intermediate lithium polysulfides (Li 2 S n , 4 ≤ n ≤ 8) during charge/discharge process. [7][8][9] Over the past decades, massive efforts like encapsulating S 8 in conductive matrix, [10][11][12][13] protective coating layers, [14][15][16] and inducing interlayer between cathode and separator, [17][18][19] have been made to manipulate this deficiency, aiming to lighten shuttling and migration of Li 2 S n during long-term cycling and to improve the electrode kinetics. 2D materials with large specific area, such as graphene oxides (GOs), [20][21][22][23][24] MnO 2 , [25] Co 4 N, [26] MXene, [27] provide numerous anchoring sites and have been successfully employed as cathode hosts to suppress shuttling and migration of Li 2 S n in the Li-S batteries. Usually, heteroatoms doping is a general modification technique to further increase the polarity of 2D materials to adsorb Li 2 S n , giving birth to nitrogen-doped graphene, [28] nitrogen-doped MXene, [29] cobalt-doped porous carbon, [30] molybdenum-doped MoO 3 , [31] etc. However, the doping amount is very limited, which seriously restricts the improvement of their electrochemical performance. Comparing with the traditional doping strategy, intercalation can induce more heteroatoms in their van der Waals gap with good uniformity and change the properties of 2D materials more significantly. [32] For example, in our previous study, we proved that the n-type semiconducting SnS 2 can turn to a p-type semiconductor or metal after intercalation of different transition metal atoms. [33] Besides the electrical properties, the electrochemical properties of 2D materials might also be tuned effectively by this intercalation strategy.Here, ultrathin 2D layered α-MoO 3 nanoribbons with thickness of ≈10 nm have been synthesized and selected as the host. The strong polarity of MoO 3 together with its high specific surface area provides numerous active sites to bind sulfur species effectively, thus suppressing the "shuttle effect" obviously. Intercalation of metal tin (Sn) into van der Waals gap was further used to enhance the intrinsic conductivity of MoO 3 and improve the binding energy with sulfur species. Transmission electron microscopy (TEM) proved that Sn was inserted into the van der Waals gap of MoO 3 uniformly. First-principles calculations further certify that binding energy as large as 3.01 eV Heteroatom doping strategies have been widely developed to engineer the conductivity and polarity of 2D materials to improve their performance as the host for sulfur cathode in lithium-sulfur batteries. However, further improvement is limited by the inhomogeneity and the small amount of the doping atoms. An intercalation method to improve the conductivity and polarity of 2D-layered α-MoO 3 nanoribbons is developed here, thus, resulting in much improved electrochemical performance as sulfur host with better rate and cycle performance. The first principle calculations show t...

Optimizing Redox Reactions in Aprotic Lithium–Sulfur Batteries

“…[ 160 ] For instance, metal tin (Sn) was intercalated into van der Waals gap of MoO 3 to improve the inherent conductivity of MoO 3 and enhance the binding energies with S‐species. [ 161 ] The strong polarity of MoO 3 and its large surface area provides rich active sites for binding S‐species, thereby hindering the LiPSs shuttling. The Sn‐doped MoO 3 electrode achieved initial capacity of 1390.3 mA h g −1 with high Coulombic efficiency of 99.7%.…”

Accelerated Li–S chemistry at a cooperative interface built in situ

“…To tackle these issues, extensive investigations have centered on the rational design of host materials and electrode structures. [6][7][8][9] Augmenting the interaction between LiPSs and sulfur hosts is in general regarded as an effective strategy. 10,11 In this respect, carbonaceous frameworks with heteroatom doping 12 and metal-based textural architectures encompassing oxides, 13 suldes, 14 and nitrides 15,16 have been employed to physically conne and chemically anchor LiPSs.…”

MoS2 nanorods with inner caves through synchronous encapsulation of sulfur for high performance Li–S cathodes

“…As shown in Fig. 1 (a and b), the MoO 3 sample displays uniform nanobelts with smooth surface and average width of 200 nm, which is the conventional morphology used in other studies on MoO 3 nanobelts [32,33] . After primary sulfuration, the surfaces of the belts become rough with no distinct change in shape and size ( Fig.…”