Ultrastable Li-ion battery anode by encapsulating SnS nanoparticles in sulfur-doping graphene bubble film
As an anode electrode material for lithium ion batteries, SnS has a high specific capacity and has received widespread attention, but its practical application is still hindered by low reversibility of conversion reaction and large irreversible capacity caused by solid electrolyte interphase (SEI). In this paper, SnS nanoparticles are encapsulated into sulfur-doping graphene bubble film (SnS@G) by a scalable electrostatic self-assembly of SnS2/graphene oxide and hexadecyl trimethyl ammonium bromide, then followed by thermal decomposition of SnS2 and sulfur-doping in graphene. Due to electrostatic attraction, SnS nanoparticles are tightly wrapped in multilayer graphene sheets to form a flake-graphite-like structure. Compared with the disorderly stacked SnS/graphene sheet composite, the closely packed SnS@G shows much lower specific surface area, smaller irreversible Li+ consumption and surface film resistance after lithiation. The SnS@G composite anode exhibits great initial Coulombic efficiency (83.2%), which is the highest value among the chemical synthesized SnS anodes. It also presents unprecedented cycling stability (1462 mAh g‒1 after 200 cycles at 0.1 A g-1 and 1020 mAh g‒1 after 500 cycles at 1 A g-1) and superior rate capabilities (750 mAh g-1 at 5 A g‒1) upon Li storage, which demonstrates its excellent electrochemical performance and great potential as a negative electrode material for lithium ion batteries.