Highly Stable Cycling of Silicon-Nanographite Aerogel-Based Anode for Lithium-Ion Batteries.

Rohan Patil,Håkan Olin,Deepak Dubal,Jonas Örtegren,Manisha Phadatare,Jagruti Meshram,Magnus Hummelgård,Nicklas Blomquist

doi:10.1021/acsomega.0c05214

Abstract

Silicon anodes are considered as promising electrode materials for next-generation high capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge–discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nanographite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.

Highlights

Lithium-ion batteries (LIBs) are gaining much research interest in portables devices and electric vehicles because of their high energy density and long cycle life
Most of the commercially available LIBs use graphite as an anode material. These graphite anodes cannot meet the everincreasing demand of high energy density due to their limited theoretical specific capacity of 372 mAh g−1.1−3 Among various materials, silicon is an attractive anode material for LIBs due to its high specific capacity of 4200 mAh g−1, which is more than 10 times higher than that of graphite
Various strategies have been applied to overcome this problem, including formation of silicon nanoparticles, silicon nanotubes, porous structures, etc.[6−9] Nanometer-scaled silicon particles are preferred over micronsized Si particles since nanoparticles significantly improve the cycling performance of anodes.[7,10,11]

Summary

Introduction

Lithium-ion batteries (LIBs) are gaining much research interest in portables devices and electric vehicles because of their high energy density and long cycle life. Most of the commercially available LIBs use graphite as an anode material. Silicon anodes deliver high capacity for LIBs, they normally suffer from poor cycling stability due to the large volume changes during the charge−discharge cycles.[4,5] Repeated volume fluctuations cause fracture and pulverization of the silicon particles, leading to repeated formation of a solid electrolyte interface (SEI) layer on the surface. The cracking of silicon particles is largely reduced by using nanostructured silicon, achieving good material stability.[5] nanosized particles have numerous challenges, for instance, high surface area, high production cost, and handling difficulties.[12−14] The high surface area linked with the nanoparticle size may increase the unwanted electrolyte reactions leading to the SEI layer formation on the surface. Various strategies were used for synthesizing silicon nanoparticles, nanowires, and nanospheres, the degradation of specific capacity in the initial cycles and the scalability of the material synthesis are the Received: October 26, 2020 Accepted: February 18, 2021 Published: March 1, 2021

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Results

Conclusion