A Robust and Conductive Black Tin Oxide Nanostructure Makes Efficient Lithium‐Ion Batteries Possible

Abstract

SnO₂‐based lithium‐ion batteries have low cost and high energy density, but their capacity fades rapidly during lithiation/delithiation due to phase aggregation and cracking. These problems can be mitigated by using highly conducting black SnO_2−x , which homogenizes the redox reactions and stabilizes fine, fracture‐resistant Sn precipitates in the Li₂O matrix. Such fine Sn precipitates and their ample contact with Li₂O proliferate the reversible Sn → Li _x Sn → Sn → SnO₂/SnO_2−x cycle during charging/discharging. SnO_2−x electrode has a reversible capacity of 1340 mAh g⁻¹ and retains 590 mAh g⁻¹ after 100 cycles. The addition of highly conductive, well‐dispersed reduced graphene oxide further stabilizes and improves its performance, allowing 950 mAh g⁻¹ remaining after 100 cycles at 0.2 A g⁻¹ with 700 mAh g⁻¹ at 2.0 A g⁻¹. Conductivity‐directed microstructure development may offer a new approach to form advanced electrodes.