Enhancing the performance of Si microparticle anode via aluminum citrate-assisted crosslinking and bonding

Silicon microparticle (SiMP) is the ideal anode material for developing the lithium-ion batteries (LIBs) with high energy density . However, the low Coulombic efficiency (CE) and rapid capacity fading caused by continuous pulverization upon cycling plague the industrial application of the SiMP. Herein, self-healable binders with three-dimensional network were constructed using aluminum citrate (AC) as a cross-linker. The metal coordination bonds formed between Al 3+ and partially lithiated polyacrylic acid (LPAA), and hydrogen bonds created between citrate and LPAA, promote the mechanical properties of the AC-modified PAA binders. Meanwhile, AC interacts with the Si O bonds on the SiMP surface to create Si O Al bonds, boosting the binding between the SiMP and LPAA. When the SiMP anode with the AC-modified binders is discharged and charged, the strain resulted from the large volume change of SiMP is relieved by the dynamic fracture and reconstruction of the hydrogen bonds and Al 3+ coordination bonds, thus ensuring the integrity of electrode. The SiMP electrode fabricated with the binder of LPAA and AC at a mass ratio of 10:1 reveals an initial CE of 91.1 %, and retains a reversible capacity of 2107.6 mAh g −1 after 100 cycles at 1.0 A g −1 . The AC-modified PAA binder with the simple fabrication process and low-cost components is capable of applying in the practical LIBs with the SiMP anode. Aluminum citrate (AC) was used to modify Si microparticles (SiMPs) via interacting with the Si O bonds on the SiMPs surface to create Si O Al bonds, and boost the partially lithiated polyacrylic acid to crosslink into three-dimensional network. The AC-modified binder with strong adhesion, superior self-healing ability and mechanical properties could tenaciously bind with the SiMPs, so the electrode reveals a high initial Coulombic efficiency (≥ 90.3 %) and greatly enhanced performance. • Aluminum citrate (AC) as a crosslinker favors to form three-dimensional network. • AC interacts with the Si O bonds on micro-Si surface to create Si O Al bonds. • The Si O Al bonds enhance the binding of the Si and polyacrylic acid (PAA) binder. • The modified PAA reveals strong adhesion, self-healability and mechanical property. • The micro-Si anode with the AC-modified binder reveals superior cycling stability.