Bulk SnO_x@C composite for improved lithium storage

Preparation of nanometer-sized SnO₂@C composites has been identified as an effective strategy for alleviating the huge volume expansion issue of the SnO₂ anodes. Due to the low tap density, however, SnO₂@C anodes with nanometer-sizes are unfavorable to be practically applied in lithium-ion batteries. Therefore, the micrometer-sized bulk SnO₂@C with a comparable performance could be a more promising anode material for lithium-ion batteries with high energy and power densities than that of its nanometer-sized counterparts, because the micrometer-sized SnO₂@C would have much higher tap density as compared to its nanometer-sized counterparts. But, there are few work about micrometer-sized SnO₂@C with satisfying performance are reported so far. Herein, a micrometer-sized SnO₂@C composite, composed of ultrafine SnO₂/Sn (SnO_x) nanoparticles embedding into bulk carbon matrix, has been prepared by a facile one-pot hydrothermal approach. More importantly, it exhibits outstanding lithium storage performance which can be comparable with and even better than that of state-of-the-art nanometer-sized counterparts, delivering high capacities of 885.8 and 637.2 mAh g⁻¹ at 200 and 1000 mA g⁻¹ after 360 and even 1000 cycles, respectively. It is demonstrated that thus performance is mainly due to the perfect synergistic effect of components and architecture. This work may also open up a broader vision into developing high performance SnO₂-based anodes.