Overcoming the Challenges of Freestanding Tin Oxide‐Based Composite Anodes to Achieve High Capacity and Increased Cycling Stability.

Zoller, Florian; Häringer, Sebastian; Böhm, Daniel; Illner, Hannah; Döblinger, Markus; Sofer, Zdene˘k; Finsterbusch, Martin; Bein, Thomas; Fattakhova‐Rohlfing, Dina

Freestanding electrodes are a promising way to increase the energy density of the batteries by decreasing the overall amount of electrochemically inactive materials. Freestanding antimony doped tin oxide (ATO)‐based hybrid materials have not been reported so far, although this material has demonstrated excellent performance in conventionally designed electrodes. Two different strategies, namely electrospinning and freeze‐casting, are explored for the fabrication of ATO‐based hybrid materials. It is shown that the electrospinning of ATO/carbon based electrodes from polyvinyl pyrrolidone polymer (PVP) solutions was not successful, as the resulting electrode material suffers from rapid degradation. However, freestanding reduced graphene oxide (rGO) containing ATO/C/rGO nanocomposites prepared via a freeze‐casting route demonstrates an impressive rate and cycling performance reaching 697 mAh g−1 at a high current density of 4 A g−1, which is 40 times higher as compared to SnO2/rGO and also exceeds the freestanding SnO2‐based composites reported so far. Antimony doping of the nanosized tin oxide phase and carbon coating are thereby shown to be essential factors for appealing electrochemical performance. Finally, the freestanding ATO/C/rGO anodes are combined with freestanding LiFe0.2Mn0.8PO4/rGO cathodes to obtain a full freestanding cell operating without metal current collector foils showing nonetheless an excellent cycling stability.

ANODES; CARBON electrodes; CARBON nanofibers; ENERGY density; TIN; GRAPHENE oxide; CYCLING competitions

Advanced Functional Materials, 2021, Vol 31, Issue 43, p1

1616-301X

Academic Journal

10.1002/adfm.202106373