Self-healing alginate–carboxymethyl chitosan porous scaffold as an effective binder for silicon anodes in lithium-ion batteries

Abstract

Polymer binder plays a pivotal role in electrochemical performance of high-capacity silicon (Si) anode that usually suffers from severe capacity fading due to enormous substantial volume change of Si during cycling. In an effort to find efficient polymer binder that could mitigate such capacity fading, alginate-carboxymethyl chitosan (Alg-C-chitosan) composite polymer was investigated as a low-cost watersoluble binder for silicon anodes in lithium-ion batteries. The electrostatic interaction between carboxylate (-COO -) of Alg and protonated amines (-NH 3 ? ) of C-chitosan forms a selfhealing porous scaffold structure. Synergistic effect on the enhanced porous scaffold structure and self-healing electrostatic interaction of Alg-C-chitosan binder effectively can tolerate the tremendous volume change of Si and maintain an integrated electrode structure during cycling process. The Si nanopowder electrodes with Alg-C-chitosan composite binder exhibit an excellent cycling stability, with a capacity of 750 mAhÁg -1 remaining after 100th cycling. In addition, an extraordinary areal capacity of 3.76 mAhÁcm -2 is achieved for Si-based anodes with Alg-C-chitosan binder.

The Electrochemical Performance of Silicon Nanoparticles in Concentrated Electrolyte

“…The electrode slurries were then coated onto ac opper foil (10 mmt hickness) and dried at room temperature for 12 h. [28] The active material mass loading was 0.2-0.3 mg cm À2 with at hickness of 5-10 mma fter pressing. 99.98 %, Shandong Hwanon Material Co.,L td.)…”

“…The binder gel solutions were prepared by dissolving C-chitosan (CS, Aladdin) and sodium alginate (NaAlg, Sigma-Aldrich) in water.T he mass ratio for Si/S-p/VGCF/ CS/NaAlg was 45:28:2:12.5:12.5. The electrode slurries were then coated onto ac opper foil (10 mmt hickness) and dried at room temperature for 12 h. [28] The active material mass loading was 0.2-0.3 mg cm À2 with at hickness of 5-10 mma fter pressing. All these electrodes were dried at 100 8Cu nder vacuum for 12 hb efore transferring to an argon-filled glovebox for coin cells preparation.…”

Polymer Binders Constructed through Dynamic Noncovalent Bonds for High‐Capacity Silicon‐Based Anodes

“…Wu et al developed ap orouss caffold structured binder by using the ionic interaction between NaAlg and chitosan, named NaAlg-C-chitosan (as shown in Figure 12 a), which was simply synthesized by blending two polymers in distilled water. [51] The ionic bondingb etween the carboxylate of NaAlg and protonated aminog roup was formed at room temperature, resulting in as elf-healable porous scaffold structured material with enhanced mechanical properties.T he interaction of ionic bonding was demonstrated by FTIR analysisa ss hown in Figure 12 b. The peaks at 1640 cm À1 and 1560cm À1 corresponding to C=Oa nd NÀH, respectively,w ere replaced by a new peak lying at 1620 cm À1 ,i ndicating the formationo fi onic bonding.…”

“…b) FTIR spectra of C-chitosan, NaAlg, and NaAlg-C-chitosan. [51] c) Comparative cycling performanceofS i electrodes with PVDF, CMC-SBR, NaAlg,C -chitosan, and NaAlg-C-chitosan binders. [51] mately 91 %e ven after 5000 cycles.…”

“…[51] c) Comparative cycling performanceofS i electrodes with PVDF, CMC-SBR, NaAlg,C -chitosan, and NaAlg-C-chitosan binders. [51] mately 91 %e ven after 5000 cycles. Although improved cycling performance is seen in complexes with hydrophobic guests, AD is chosen as the hydrophobic guest owing to its excellent affinity and selective bonding with b-CD.…”