Heterostructured Nanocube‐Shaped Binary Sulfide (SnCo)S2 Interlaced with S‐Doped Graphene as a High‐Performance Anode for Advanced Na+ Batteries
A heterogeneous nanocube‐shaped binary sulfide interlaced with S‐doped graphene is fabricated as an anode for sodium storage. Its unique heterointerfacial structure can increase reaction kinetic and maintain structural stability, resulting in ultrahigh rate capacity with ultralong life. Furthermore, the fundamental mechanism of synergistic effects for heterogeneous is demonstrated by in‐situ measurements, confirming that constructing a stable Sn/Na2S interface can effectively enhance the reversibility of the conversion reaction. Abstract Heterostructuring electrodes with multiple electroactive and inactive supporting components to simultaneously satisfy electrochemical and structural requirements has recently been identified as a viable pathway to achieve high‐capacity and durable sodium‐ion batteries (SIBs). Here, a new design of heterostructured SIB anode is reported consisting of double metal‐sulfide (SnCo)S2 nanocubes interlaced with 2D sulfur‐doped graphene (SG) nanosheets. The heterostructured (SnCo)S2/SG nanocubes exhibit an excellent rate capability (469 mAh g−1 at 10.0 A g−1) and durability (5000 cycles, 487 mAh g−1 at 5.0 A g−1, 92.6% capacity retention). In situ X‐ray diffraction reveals that the (SnCo)S2/SG anode undergoes a six‐stage Na+ storage mechanism of combined intercalation, conversion, and alloying reactions. The first‐principle density functional theory calculations suggest high concentration of p–n heterojunctions at SnS2/CoS2 interfaces responsible for the high rate performance, while in situ transmission electron microscopy unveils that the interlacing and elastic SG nanosheets play a key role in extending the cycle life.
Published in: "Advanced Functional Materials".