Binary Carbon Modification Promoting the Electrochemical Performance of Silicon Anode for Lithium‐Ion Batteries

Abstract

As the research on lithium-ion battery cathode materials gradually breaks through the saturation, the anode materials for lithium-ion batteries have received wide attention because of their promising future. Silicon electrodes, in particular, are attracting increasing attention. In this paper, the Si/G precursor was achieved by simple mechanical ball milling. Two silicon based composite electrode materials Si@TA and Si@TA-G were synthesized by spontaneous polymerization of tannic acid on precursor surface in Tris buffer solution. For the poor electrical conductivity of silicon, graphite was added as a carbon source to avoid the direct contact between silicon and electrolyte during charge/discharge process by forming tannic acid coating on silicon surface.The Si@TA composites achieve a discharge specific capacity of 927.4 mAh g À 1 at 100 mA g À 1 current density after 50 cycles with a retention rate of 87.1 % while the reversible capacity of Si@TA-G is 1249.8 mAh g À 1 with a retention rate is 93.6 %. This unique composite method provides new insights into the modification of silicon anode materials.