Mechanical mismatch-driven rippling in carbon-coated silicon sheets for stress-resilient battery anodes

Abstract

High-theoretical capacity and low working potential make silicon ideal anode for lithium ion batteries. However, the large volume change of silicon upon lithiation/delithiation poses a critical challenge for stable battery operations. Here, we introduce an unprecedented design, which takes advantage of large deformation and ensures the structural stability of the material by developing a two-dimensional silicon nanosheet coated with a thin carbon layer. During electrochemical cycling, this carbon coated silicon nanosheet exhibits unique deformation patterns, featuring accommodation of deformation in the thickness direction upon lithiation, while forming ripples upon delithiation, as demonstrated by in situ transmission electron microscopy observation and chemomechanical simulation. The ripple formation presents a unique mechanism for releasing the cycling induced stress, rendering the electrode much more stable and durable than the uncoated counterparts. This work demonstrates a general principle as how to take the advantage of the large deformation materials for designing high capacity electrode.

Low‐Temperature Reduction Strategy Synthesized Si/Ti3C2 MXene Composite Anodes for High‐Performance Li‐Ion Batteries

“…Silicon (Si) is one of the most promising anode materials for next‐generation lithium‐ion batteries (LIBs), due to its high theoretical capacity (4200 mAh g −1 ), relatively low discharge potential (<0.5 V vs Li/Li + ), and abundant earth reserves . However, the commercialization of Si anodes for LIBs has always been stuck by rapid capacity fading resulted from the unavoidable large volume expansion and the intrinsically poor electrical conductivity of Si . Tremendous efforts have been made to improve the performance of Si‐based LIBs, such as fabricating Si particles with nanoscale size, constructing a variety of nanostructures .…”

Constraint spaces in carbon materials

“…The thickness and lateral size of the Si akes was controlled to be 50 nm and a micrometer, respectively. 72 Carbon coating of the Si akes was performed by heating in acetylene gas at 900 C, resulting in the carbon content of 7 wt% and the thickness of about 10 nm. The non-porous structure of the pristine and carbon-coated Si akes with a low surface area of ca.…”

“…The structural deformation of the carbon-coated Si ake was monitored by in situ TEM under a bias of À3 V and 3 V, respectively, where a ake was mounted on a Pt wire connected to the Li 2 O/Li probe; the Li metal and the LiO 2 layer serve as the counter electrode and the solid electrolyte, respectively. 72 The structural deformation of the ake in the rst two lithiation/delithiation cycles was schematically illustrated in Fig. 22.…”

Graphene Nanoscrolls with Confined Silicon Nanoparticles as a Durable Anode for Lithium‐Ion Batteries

“…Among them, reducing silicon dimension (nanoparticle, nanowire or nanosheet), exploiting robust binders and particularly designing hierarchical or confined structures are the main routes to enhance the electrochemical performances of silicon‐based anodes . Nanometer Si anodes not only can improve the kinetics of carriers but also suppress the material pulverization owing to sufficient stress relaxation . Lastly, Fu et al.…”