Metallic tin nanodots inducing an interfacial adsorption–insertion mechanism for carbon nano-honeycombs with enhanced sodium storage

Abstract

Herein, a new Na⁺ migration pathway of an interfacial adsorption–insertion mechanism is proposed for Sn nanodots modulating N-doped carbon nano-honeycombs (denoted as Sn/N-CNs) to enhance electrochemical kinetics. Benefitting from the unusual coordination ability of melamine with metallic Sn nanodots and the two-dimensional network formed by hydrogen bonding between melamine and cyanuric acid, the Sn/N-CNs were successfully prepared by a facial supramolecular assembly one-pot method and following carbonization treatment. Significantly, the introduction of metallic Sn nanodots and nitrogen-doping facilitate the nucleation and uniform growth of carbon nano-honeycombs and generate abundant N–Sn interface bonds, which can modulate the electronic structures of carbon atoms, promote the rapid adsorption/diffusion of Na⁺, accelerate the ionic/electronic kinetics and guarantee the improved specific capacity and cycling capability. As a result, the as-prepared Sn/N-CNs deliver a high specific capacity of 770.1 mA h g⁻¹ at 0.1 A g⁻¹, and an advanced ultra-long cycle lifespan of over 10 000 times with a specific capacity of 253.1 mA h g⁻¹ at a large current density of 5 A g⁻¹ (0.0086% loss per cycle).