Layer-by-Layer Engineered Silicon-Based Sandwich Nanomat as Flexible Anode for Lithium-Ion Batteries

Abstract

Lithium-ion batteries with high electrochemical performance and stable mechanical compliance are pivotal to propel the advanced wearable electronics forward. Herein, a high-conductive flexible electrode densified from multilayer lamellar unit cells with the silicon-based sandwich structure is rationally designed by molecular engineering. Silicon nanoparticles can be uniformly anchored to the surface of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose (TOBC) aerogel through hydrogen bonding, which effectively relaxes the drastic volume expansion of the Si-based anode. The graphite microsheets (GMs) attached on silicon nanoparticles allow the porous aerogel network to maintain excellent electrical connection in all directions, and after being switched to compact film, the conductive network enables a robust contact with silicon nanoparticles. As a result, the Si-based nanomat anode exhibits reliable cycling stability (639.4 mA h g–1 after 400 cycles at 1.0 A g–1) and enhanced rate capability (298.6 mA h g–1 at 1.6 A g–1). Notably, instead of conventional polyolefin separators, TOBC-reinforced silica aerogel is fabricated as an advanced separator to integrate the flexible all-in-one full-cell with freestanding GM/TOBC/silicon (GM/TOBC/Si) anode and GM/TOBC/LiFePO4 cathode. Driven by the unique structure and functional component, the flexible all-in-one lithium-ion batteries showcase exceptional deformation tolerance yet impressive charge/discharge behavior.

Porous Si/Cu Anode with High Initial Coulombic Efficiency and Volumetric Capacity by Comprehensive Utilization of Laser Additive Manufacturing-Chemical Dealloying

“…5 However, a Si-based anode generally suffers from a series of problems. The main challenges for practical applications include the following: (i) huge volume change of Si in repeated charge−discharge cycles, causing pulverization as well as continuous formation of unstable solidelectrolyte interphase (SEI); 6 (ii) irreversible capacity loss at the first cycle, leading to low initial coulombic efficiency (ICE); 7 and (iii) small packing density of active materials, resulting in low volumetric capacity. 8 To suppress volume change during charge−discharge cycles, nano-engineered Si materials have been intensively studied and successfully applied to prevent pulverization, as their large surface-to-volume ratio can facilitate stress relaxation.…”

“…However, a Si-based anode generally suffers from a series of problems. The main challenges for practical applications include the following: (i) huge volume change of Si in repeated charge–discharge cycles, causing pulverization as well as continuous formation of unstable solid-electrolyte interphase (SEI); (ii) irreversible capacity loss at the first cycle, leading to low initial coulombic efficiency (ICE); and (iii) small packing density of active materials, resulting in low volumetric capacity …”

Natural Cellulose Substance Based Energy Materials

“…The microscroll nanoarchitecture holds new insights in developing large‐scale and actual capacity of the commercial cellulose‐based carbon/silicon electrodes for LIBs. In addition, to fabricate the Si‐based anode with durable cyclability and mechanical property, Si nanoparticles and graphite microsheets were assembled on 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) oxidized bacterial cellulose aerogel through hydrogen bonding to form a free‐standing anode for LIBs, which showed an exceptional deformation tolerance, reliable stability, and improved rate capability [37] …”

An Overview of Bacterial Cellulose in Flexible Electrochemical Energy Storage

“…[136] Therefore, developing as train-free Si-based anode with good flexibility and satisfactory electrochemical performances has been identified as an attractive and challenging task for satisfying the needs of flexible LIBs that are durable under rolling and bending. Zhou et al [131] reported the preparation of aS i-based self-standingf ilm with ac ompact sandwich-like structure in the presence of BC and graphitem icrosheets (GM) and explored its application in flexible all-in-oneL IBs (Figure 17 a). The strongi nterconnections from hydrogen bonding between OH/COOHg roups of BC nanofibers and silanol functionalities ensure uniform distributiono ft he generatedS i nanoparticles.…”