Haoxiang Zhong

Micro/nano-structured SnS2 negative electrodes using chitosan derivatives as water-soluble binders for Li-ion batteries

Micro/nano-structured SnS2 was prepared by a hydrothermal method using biomolecular l-cysteine and SnCl4·5H2O as sulfur source and tin source, respectively. The electrochemical performances of SnS2 electrodes were investigated using water-soluble binders of carboxymethyl chitosan (C-chitosan) and chitosan lactate, and compared with the conventional water-soluble sodium carboxymethyl cellulose (CMC) and non-aqueous polyvinylidene difluoride (PVDF). SnS2 electrode using the water-soluble binders (C-chitosan, chitosan lactate, and CMC) showed higher initial coulombic efficiency, larger reversible capacity, and better rate capabilities than that of PVDF. In addition, SnS2 electrode using C-chitosan binder exhibited somewhat worse cycling stability, but better rate capability at a high rate of 5C than CMC.

Facile synthesis of nanostructured Li4Ti5O12/PEDOT:PSS composite as anode material for lithium-ion batteries

A poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coated Li4Ti5O12 (LTO/PP) composite is synthesized by a facile and convenient approach, which involves dispersing LTO in an aqueous solution of PEDOT:PSS, followed by rotary evaporation accompanied by an ultrasonic procedure. After the coating process, LTO is covered by a homogeneous PEDOT:PSS layer, which effectively improves the electrical conductivity and processing capability of LTO to form a more homogeneous electrode sheet, and thus impart more favorable electrochemical kinetics as compared with the pristine LTO electrode. The LTO/PP electrode exhibits better reversible capacity and rate capability compared with the LTO electrode, delivering a reversible capacity of 177.2 mA h g−1 at 0.1C and reaching a capacity of 169.1 mA h g−1 with a capacity retention of 97.8% after 100 cycles at 0.5C. At the rate of 10C, the LTO/PP electrode delivers a capacity as high as 161.1 mA h g−1 (91.0% of the value achieved at 0.1C), as compared to 144.5 mA h g−1 for the pristine LTO electrode.