A naphthalene organic cage captured sodium polysulphide as cathode materials for lithium-ion sulfide batteries

Organic molecules have recently been engaged in the field of energy storage such as lithium, sodium and lithium-sulfur batteries due to the controllable functional groups. In this work, a naphthalene porous organic cage (IIC-1) is developed to capture sulfide and used as lithium-sulfur anode. The electron-deficient skeleton of this cage has a good adsorption toward electron-rich Na2S5 in aqueous solution (490 mg/g) and this host-guest complex (IIC-1@ Na2S5) exhibited typical charge-discharge plateaus of sulfur. As lithium-sulfur anode, the IIC-1@ Na2S5 obtained 852 mAh g−1 specific capacity and a good stability with only 0.05% per cycle after 1000 cycles. The easy imine condensation synthesize method provides much convenient and opportunity for the prospect of organic electrochemical materials. •A naphthalene diimide-derivate porous cage (IIC-1) structure was newly designed.•One-step synthesis method -- schiff base condensation reaction.•Efficient adsorption of polysulfide in water.•Engagement of porous cage in lithium-sulfur energy storage.