The severe volume expansion/contraction change, leading to the limited cycling stability and rate capability, is a critical issue to commercialize the Sn material as an anode for lithium-ion batteries due to the formation/decomposition of the Li22Sn5 alloy phase during the charge/discharge step. The use of matrix material with an elastic ability is an effective strategy to suppress volume change, by forming a composite system. Herein, a Sn-C anode material, comprising of a homogeneously dispersed Sn nanoparticle (≤ 10 nm) in a polymerized C60 (PC60) matrix, is prepared by plasma-assisted thermal evaporation coupled by chemical vapor deposition. The self-relaxant elastic characteristics of PC60 are successfully alleviate the significant volume changes by absorbing the stress–strain generated from the Sn nanoparticles. Meantime, Sn nanoparticles surrounded by a thin SnO2 layer possess a multilayer structure with a suitable inter-particle spacing to further alleviate the nanoparticle-aggregation during cycles. The diffusion and transport rate of Li-ions are enhanced by the built-in electric field formed in the inter-particle junction of Sn/SnO2/PC60 ternary structure. The Sn-PC60 anode shows an excellent capacity retention of 97.18% after 5000 cycles at a current density of 1000 mA g-1 with a discharge capacity of 834.25 mAh g-1 in a half-cell configuration. The rate-capability performance of this Sn-PC60 half-cell exhibites a discharge capacity of 544.33 mAh g-1 at a 100-fold higher current density of 10 000 mA g-1. In addition, the full-cell based on Sn-PC60 anode and LiCoO2 cathode exhibits a discharge capacity of 801.04 mAh g-1 and an areal capacity of 1.57 mAh cm-2 with a capacity retention of 95.27 % after 350 cycles at a current density of 1000 mA g-1.

Plasma-polymerized C60 as an elastic matrix integrated Sn nanoparticles anode for lithium-ion batteries

2019 Fall National Meeting

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