Steric-Hindrance Effect and Self-Sacrificing Template Behavior Induced Sno 2 -Qds/Pda Hollow Nanospheres: Enhanced Structural Stability and Reaction Kinetics for Long-Cyclic Li-Ion Half/Full Batteries

Abstract

Tin-based anode materials with high theoretical specific capacity are subject to huge volume expansion and poor reaction reversibility, leading to degradation of battery performance. Herein, the steric-hindrance effect and self-sacrificing template behavior of polydopamine were firstly developed to induce the formation of hollow nanospheres assembled by ultrafine SnO 2 quantum dots (SnO 2 -QDs) and nitrogen-doped carbon, containing residual polydopamine (PDA) cores. The SnO 2 -QDs/PDA hollow nanospheres could effectively accommodate the volume expansion and maintain the structural stability. More importantly, the PDA core could capture oxygen free radicals produced by the charge/discharge process and involved in the evolution of the SEI layer, achieving the enhanced electrochemical reaction kinetics. The optimized SnO 2 -QDs/PDA anode shows a specific capacity of 898 mAh g -1 after 300 cycles at 0.3 A g -1 , and scarcely capacity attenuation after 1500 cycles at 1 A g -1 . Even after 200 cycles, the anode in the SnO 2 -QDs/PDA||LFP full battery gives a reversible capacity of 489 mAh g -1 at 0.3 A g -1 , with a capacity retention of 77%. This work casts new slight on the tin-based anode materials and interface optimization.

Keywords: lithium ion batteries, SnO2 quantum dots, self-sacrifice template, oxygen radicals, polydopamine