Abstract
Silicon is investigated as one of the most prospective anode materials for next generation lithium ion batteries due to its superior theoretical capacity (3580 mAh g−1), but its commercial application is hindered by its inferior dynamic property and poor cyclic performance. Herein, we presented a facile method for preparing silicon/tin@graphite-amorphous carbon (Si/Sn@G–C) composite through hydrolyzing of SnCl2 on etched Fe–Si alloys, followed by ball milling mixture and carbon pyrolysis reduction processes. Structural characterization indicates that the nano-Sn decorated porous Si particles are coated by graphite and amorphous carbon. The addition of nano-Sn and carbonaceous materials can effectively improve the dynamic performance and the structure stability of the composite. As a result, it exhibits an initial columbic efficiency of 79% and a stable specific capacity of 825.5 mAh g−1 after 300 cycles at a current density of 1 A g−1. Besides, the Si/Sn@G–C composite exerts enhanced rate performance with 445 mAh g−1 retention at 5 A g−1. This work provides an approach to improve the electrochemical performance of Si anode materials through reasonable compositing with elements from the same family.
Highlights
Lithium-ion batteries (LIBs) affect many aspects of our lives because of their high energy density, low self-discharge rate and good rate capacity [1,2,3]
Graphite has been used in LIBs as anode material for decades because of its stable capacity retention, but its theoretical capacity of 372 mAh g−1 limits the further development of LIBs with higher energy density and security [11,12,13,14].much efforts have been devoted to develop new anode materials, such as Si [15], Sn [16]
0.4 g micro-sized porous silicon and 0.1 g SnCl2 ·2H2 O are weighted and added into 20 mL distilled H2 O and magnetic stirred for 60 min at room temperature
Summary
Lithium-ion batteries (LIBs) affect many aspects of our lives because of their high energy density, low self-discharge rate and good rate capacity [1,2,3]. Silicon with high specific capacity (3580 mAh g−1 ) [24], moderate operation potential (around 0.4 V vs Li/Li+ ), environmentally benign nature and abundant reserves is considered as one of the most promising generation anode materials [25,26] Despite these advantages, some defects prevent silicon anode from being widely used: its low electronic conductivity (2 × 103 Ω·m) and structural instability upon lithiation result in inferior rate performance and rapid capacity fading [27]. The micro-sized porous Si with high performance has exhibited hopeful prospect of practical application and scalable production [12]
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