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

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 SnO₂₋ _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 _xSn → Sn → SnO₂/SnO₂₋ _x cycle during charging/discharging. SnO₂₋ _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. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim