SnO2 Quantum Dots: Rational Design to Achieve Highly Reversible Conversion Reaction and Stable Capacities for Lithium and Sodium Storage

SnO2 quantum dots ( ≈5 nm) embedded in porous N‐doped carbon matrix (SnO2/NC) are developed via a hydrothermal step combined with a self ‐polymerization process at room temperature. The ultrasmall size in quantum dots greatly shortens the ion diffusion distance and lowers the internal strain, significantly improving the conversion reaction efficiency and initial coulombic efficiency in lithium and sodium storage. AbstractSnO2 has been considered as a promising anode material for lithium ‐ion batteries (LIBs) and sodium ion batteries (SIBs), but challenging as well for the low‐reversible conversion reaction and coulombic efficiency. To address these issues, herein, SnO2 quantum dots ( ≈5 nm) embedded in porous N‐doped carbon matrix (SnO2/NC) are developed via a hydrothermal step combined with a self ‐polymerization process at room temperature. The ultrasmall size in quantum dots can greatly shorten the ion diffusion distance and lower the internal strain, improving the conversion reaction efficiency and coulombic efficiency. The rich mesopores/micropores and highly conductive N‐doped carbon matrix can further enhance the overall conductivity and buffer effect of the composite. As a result, the optimized SnO2/NC ‐2 composite for LIBs exhibits a high coulombic efficiency of 72.9%, a high discharge capacity of 1255.2 mAh g−1 at 0.1 A g−1 after 100 cycles and a long life ‐span with a capacity of 753 mAh g−1 after 1500 cycles at 1 A g−1. The SnO2/NC ...
Source: Small - Category: Nanotechnology Authors: Tags: Full Paper Source Type: research