A cation/anion-dually active metal-organic complex with 2D lamellar structure as anode material for Li/Na-ion batteries

Abstract

One of the main research hotspots for secondary batteries is to develop new electrode materials with outstanding performance. Herein, a novel metal-organic complex with two-dimensional (2D) lamellar structure, tin 1,2,4,5-benzenetetracarboxylic (Sn2BTC), is rationally designed and prepared by a simple solvothermal method. Such Sn2BTC exhibits unique cation/anion-dual capability for Li/Na storage as revealled by several ex-situ studies. Exactly, the metallic cations contribute high capacity due to the alloying reaction, while organic anions play double roles, viz., delivering capacity by the carbonyl groups and releasing the stresses from the huge volumetric changes of inorganic Sn de-/alloying during cycling owing to the high flexibility of organics. Its Li/Na-storage properties have also been significantly enhanced via self-assembly with the in-situ-added graphene oxide (GO) nanosheets, forming the nanocomposite of Sn2BTC-GO. As used for Li ion batteries, Sn2BTC-GO delivers a high reversible specific capacity of 998 mA h g−1 at 0.1 A g−1, and the corresponding capacity attenuation is only ∼0.05% per cycle during 500 cycles. Its Na-storage capacity is about 300 mA h g−1 at 0.1 A g−1. This work provide a new and profound strategy to develop advanced electrode materials (organic-inorganic hybrid) for batteries.