Stable high-capacity and high-rate silicon-based lithium battery anodes upon two-dimensional covalent encapsulation

Abstract

Silicon is a promising anode material for lithium-ion and post lithium-ion batteries but suffers from a large volume change upon lithiation and delithiation. The resulting instabilities of bulk and interfacial structures severely hamper performance and obstruct practical use. Stability improvements have been achieved, although at the expense of rate capability. Herein, a protocol is developed which we describe as two-dimensional covalent encapsulation. Twodimensional, covalently bound silicon-carbon hybrids serve as proof-of-concept of a new material design. Their high reversibility, capacity and rate capability furnish a remarkable level of integrated performances when referred to weight, volume and area. Different from existing strategies, the two-dimensional covalent binding creates a robust and efficient contact between the silicon and electrically conductive media, enabling stable and fast electron, as well as ion, transport from and to silicon. As evidenced by interfacial morphology and chemical composition, this design profoundly changes the interface between silicon and the electrolyte, securing the as-created contact to persist upon cycling. Combined with a simple, facile and scalable manufacturing process, this study opens a new avenue to stabilize silicon without sacrificing other device parameters. The results hold great promise for both further rational improvement and mass production of advanced energy storage materials.

Preparation and Characterization of Core-Shell Structure Hard Carbon/Si-Carbon Composites with Multiple Shell Structures as Anode Materials for Lithium-Ion Batteries

“…Accordingly, it is considered that the use of SCB and additional coating of the graphite nanosheets would effectively reduce an irreversible reaction with electrolytes, as deduced from the fact that the initial irreversible capacity is largely related with the formation of solid electrolyte interface (SEI) films, which is formed by the decomposition of electrolytes on the surface of electrodes [24][25][26][27][28]. This is consistent with the previous works [17,18,[29][30][31], which found that the approach using few-layer graphene and carbon coating is very effective in improving the electrochemical performance of a Si-based anode, leading to the enhancement of the structural stability, electrical conductivity and the protection of Si from exposing the electrolyte.…”

Enhanced capacity retention based silicon nanosheets electrode by CMC coating for lithium-ion batteries

“…Among the candidates for high energy density anodes, silicon (Si) is a promising candidate due to the high theoretical capacity of 4200 mAh g −1 , which is much larger than that of representative anode materials, carbon (372 mAh g −1 ) [6][7][8][9][10]. However, it has not been commercialized yet because of some critical issues including the mechanical integrity by large volume changes in the course of Li intercalations (i.e., mechanical stability) and formation of a SEI (solid electrolyte interface) layer on the surface of Si electrodes (i.e., electrochemical stability).…”

The Advance and Perspective on Electrode Materials for Metal–Ion Hybrid Capacitors

“…Si‐ and Sn‐based materials are high‐performance anode materials with desirable properties, including high earth abundance, high theoretical capacity, and low delithiation potential. [ 150 ] As alloy‐based materials, the main obstacle to developing high performance Si‐ and Sn‐based HICs is the considerable volume change in the lithiated/delithiated state, resulting in the fragmentation of electrode material. Tailoring nanostructures and combining carbon with Si‐ and Sn‐based materials are an effective proposal to mitigate the volume change and improve the electrical conductivity.…”