Design and synthesis of a 3D graphene-enhanced electrode for fast charge/ion transport for lithium storage

Abstract

Rational design and synthesis processes are very important for giving a product an excellent performance. Sn-based anode materials with a high theoretical capacity and suitable working potential usually suffer from severe capacity fading due to their inferior electronic conductivity and obvious volumetric variations, hindering their practical applications. Herein, hierarchical N doped graphene-supported SnO₂/Zn₂SnO₄ (SnO₂/Zn₂SnO₄-NG) is successfully prepared via a facile approach forming a 3D hierarchical configuration. As an anode for lithium-ion batteries, the SnO₂/Zn₂SnO₄-NG anode can reach a high reversible capacity (837 mA h g⁻¹ after 300 cycles at 0.2 A g⁻¹) and rate capability (403 mA h g⁻¹ at 5 A g⁻¹) but also show extraordinary durability. Furthermore, it exhibits an impressive rate performance and maintains superior cycling stability. Such significantly enhanced electrochemical performances of the SnO₂/Zn₂SnO₄-NG anode can be attributed to the unique structural design, which can not only effectively reduce the stress from the discharging/charging process and maintain the structural stability of the electrode during cycling but also alleviate aggregation of the active materials and facilitate electrolyte/ion transport. Meanwhile, Zn₂SnO₄ can greatly improve the electrical conductivity (confirmed by DFT calculations), and SnO₂/Zn₂SnO₄ can create more active sites for lithium storage. This work thus verifies the great potential of the SnO₂/Zn₂SnO₄-NG composite for applications as a high-performance anode material in next-generation Li storage.