Sea Urchin-Like GC-SnO2 Microsphere Composite as Anode for High-Performance Lithium-Ion Battery

Graphical This paper presents a urchin-like graphitized carbon-coated SnO₂ (GC-SnO₂) composite. Its spine-like carbon structure with branched networks alleviates stress concentration in SnO₂ anodes during cycling, enabling efficient ion transport. This design enhances high-rate performance and structural stability of lithium-ion batteries. Tin dioxide (SnO₂) has emerged as a promising anode for lithium-ion batteries (LIBs) due to its high theoretical capacity and natural abundance. However, it suffers from severe volume expansion during lithiation/delithiation processes and limited rate capability. To address these challenges, this work rationally designed an urchin-like-graphitized carbon (GC)-SnO₂ microsphere composite (denoted for GC-SnO 2 ) through hydrothermal synthesis followed by controlled annealing. The hierarchical architecture consists of hollow SnO 2 nanospheres encapsulated within branched graphitized carbon protrusions, forming a hierarchically porous network. This structural design enables three key advantages: (1) accelerated Li + diffusion through interconnected channels, (2) stress buffering via spiny carbon branches to mitigate SnO 2 pulverization, and (3) enhanced conductivity through conformal GC coating. Benefiting from these synergistic features, the GC-SnO 2 anode exhibits outstanding cyclability, maintaining 765 mA h g −1 after 100 cycles at 0.2 A g −1 . Notably, it achieves 538 mA h g −1 at 2 A g −1 over 1000 cycles, surpassing bare SnO 2 (89 mA h g −1 ) and exceeding the performance of most reported SnO 2 -based anodes. This work provides an effective strategy for designing stress-tolerant oxide/carbon composites toward high-energy-density LIBs.