A Free‐Standing Polyaniline/Silicon Nanowire Forest as the Anode for Lithium‐ion Batteries

Abstract

Despite its high theoretical capacity, silicon anode has limited intrinsic conductivity and experiences significant volume changes during charge-discharge. To overcome these issues, facile metal-assisted chemical etching and in-situ polymerization of aniline are employed to produce a dense 1D polyaniline/silicon nanowire forest without noticeable agglomeration as a free-standing anode for lithium-ion batteries. This hybrid electrode possesses high cycling performance, delivering a stable capacity capped at 2 mAh cm À 2 for 346 cycles of charge-discharge. Maximum capacity of 2 mAh cm À 2 is also achievable at high-rate cell testing of 2 mA cm À 2 , which cannot be obtained by the anode with plain silicon wafer and silicon nanowire only. The introduction of polyaniline on the silicon nanowire is shown to reduce the solid electrolyte interface (SEI) resistance, stabilize the SEI layer, further alleviate the effect of volume changes, and boost the conductivity of the hybrid anode, resulting in the high electrochemical performance of the anode.

Conductive Polymer Frameworks in Silicon Anodes for Advanced Lithium-Ion Batteries

“…Instead of overlaying a regular silicon particle anode, PANI has also been utilized to coat silicon nanowire anode (Figure d) . The Si nanowire was fabricated using metal-assisted chemical etching as an anisotropic etching method .…”

“…(d) Fabrication process and (e) cycling stability performance of PANI-coated silicon nanowire anode. Adapted with permission from ref . Copyright 2022 Wiley-VCH GmbH.…”

“…Instead of overlaying a regular silicon particle anode, PANI has also been utilized to coat silicon nanowire anode (Figure 4d). 78 The Si nanowire was fabricated using metal-assisted chemical etching as an anisotropic etching method. 108 This array of Si nanowires was built to accommodate strain relaxation during volume change in charge−discharge.…”

Para Grass-Derived Porous Carbon-Rich SiOx/C as a Stable Anode for Lithium-Ion Batteries

“…Silicon-based anodes are an attractive option for lithium-ion batteries (LIBs) owing to their large theoretical specific capacity (∼4200 mAh g –1 ), acceptable operating voltage (discharge voltage of 0.4 V vs Li/Li + ), and a wide range of available precursors. − However, a significant volumetric change of up to 380% takes place during lithium ion insertion and extraction into and from silicon, resulting in activity loss and instability during cycling. − Compared to pristine silicon, silicon oxide (SiO x ) has smaller volume expansion (160–200%), simpler synthesis procedures, and lower production cost but a smaller theoretical capacity (2680 mAh g –1 ). , During the initial lithiation process, SiO x generates inert Li 2 O and lithium silicates (Li 4 SiO 4 , Li 2 Si 2 O 5 ) that serve as a buffer during volume changes and assist in sustaining its structural integrity. ,,, …”

Preparation of a SiO2@Carbon Sphere/SiO2−CNF Multilayer Self‐standing Anode Prepared via an Alternate Electrospraying – Electrospinning Technique

“…However, the SiO 2 also exhibits weaknesses, such as poor conductivity and volume expansion (300%), which results in low capacity and rate performance. [12][13][14] To tackle those disadvantages, certain strategies were proposed, for instance, (i) decreased particles size in nanoscale and (ii) fabricated composites anode with carbonaceous materials; (iii) construct appropriate structure to relieve the stress caused by expansion. Corresponding research have devoted to compound silica with carbonaceous materials, such as SiO 2 @graphene, [15] SiO 2 @C@graphene spheres, [16] SiO 2 @porous carbon, [17,18] SiO 2 /CNTs composites materials and SiO 2 /Co/C composite.…”