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 Li₂ O matrix. Such fine Sn precipitates and their ample contact with Li₂ O 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.

Keywords: conductive tin oxide; lithium-ion batteries (LIBs); molten-aluminum reduction method; reversible redox reaction.