Tunable Surface Selenization on MoO₂‐Based Carbon Substrate for Notably Enhanced Sodium‐Ion Storage Properties

Abstract

Transition metal chalcogenides with high theoretical capacity are promising conversion‐type anode materials for sodium ion batteries (SIBs), but often suffer from unsatisfied cycling stability (hundreds of cycles) caused by structural collapse and agglomerate. Herein, a rational strategy of tunable surface selenization on highly crystalline MoO2‐based carbon substrate is designed, where the sheet‐like MoSe2 can be coated on the surface of bundle‐like N‐doped carbon/granular MoO2 substrate, realizing partial transformation from MoO2 to MoSe2, and creating b‐NC/g‐MoO2@s‐MoSe2‐10 with robust hierarchical MoO2@MoSe2 heterostructures and strong chemical couplings (MoC and MoN). Such well‐designed architecture can provide signally improved reaction kinetics and reinforced structural integrity for fast and stable sodium‐ion storage, as confirmed by the ex situ results and kinetic analyses as well as the density functional theory calculations. As expected, the b‐NC/g‐MoO2@s‐MoSe2‐10 delivers splendid rate capability and ultralong cycling stability (254.2 mAh g−1 reversible capacity at 5.0 A g−1 after 6000 cycles with ≈89.0% capacity retention). Therefore, the tunable surface strategy can provide new insights for designing and constructing heterostructures of transition metal chalcogenides toward high‐performance SIBs.

Cobalt Selenide Hollow Polyhedron Encapsulated in Graphene for High‐Performance Lithium/Sodium Storage

“…[5] The reason of this instability is the large size of Na + (1.02 Å) which makes it difficult to intercalate in materials, even if intercalated, the material structures may suffer from extreme volume distortion, eventually leading to rapid capacity fading during charge/discharge processes. [6] Exploiting suitable anode materials, which can achieve high capacities and accommodate the Li and Na ion with small volume expansion, is particularly critical for the development of conventional LIBs and SIBs. [7][8][9] Transition-metal selenides (TMSs) with narrow/zero bandgap properties and high specific theoretical capacities are extensively investigated as anode materials for LIBs/SIBs.…”

Biomineralized Mesocrystal KCl Microreactor for Solid‐State Synthesis of Non‐Oxide Nanomaterials

“…The kinetics analysis shows a dominant capacity-controlled behavior of the MoS x Se 2−x /C anode with the 84.9% capacity contribution (Figures S13 and S14, Supporting Information). [48,49] The GITT and EIS results indicate the smaller reaction resistance and the charge transfer resistance of the MoS x Se 2−x /C anode than other comparable electrodes, showing the fast charge transition behavior (Figure 5e,f and Figure S15, Supporting Information). As displayed by Figure 5g, the microstructure of the MoS x Se 2−x /C anode can remain intact without collapse after 100 cycles at 2 A g −1 , confirming its good electrochemical stability.…”

MoO2/C composites prepared by tartaric acid and glucose-assisted sol-gel processes as anode materials for lithium-ion batteries

“…S4a) and after (Fig. S4b) cycling reveals that the individual particles change their surface texture, which is likely due to the known degeneration mechanisms such as SEI formation [51] and/or agglomeration. Pulverization as a possible degeneration phenomenon for MoO 2 /C-G(M) seems to be less critical as the high-resolution SEM images show that even after 60 cycles the binder network is intact and no clear cracks are visible.…”