Sodium-ion batteries (SIBs) are promising for large-scale energy storage due to their high cost-effectiveness and safety. Alloy anodes exhibit significantly higher specific capacities compared to those of carbonaceous anode materials, holding great promise for enhancing the energy density of SIBs. However, their practical application is severely hindered by substantial volume expansion, sluggish reaction kinetics, and continuous fracture reformation of the solid-electrolyte interphase (SEI). Here, a multifunctional composite binder system was designed for the Sn anode, which was composed of poly(ethylene oxide) (PEO), sodium alginate (SA), and sodium bis(trifluoromethylsulfonyl)imide (NaTFSI). The PEO-SA-NaTFSI (PSN) binder integrates ternary synergistic functions: robust adhesion between the active material and current collector, enhanced Na+ transport kinetics, and formation of a stable NaF-rich SEI. Therefore, the Sn-PSN anode achieves an outstanding sodium storage performance with a high capacity of 583.4 mA h g–1 at a current density of 10 A g–1 and 77% capacity retention after 1500 cycles. In addition, the Sn-PSN||Na3V2(PO4)3 full battery can maintain 81% capacity after 200 cycles with an electrode energy density of 169.0 W h kg–1. This work provides a multifunctional binder design strategy with broad application prospects for high-performance anodes of SIBs.
Chen Zhao,Cheng Zheng,Qian Yao,Chenghui Zhang,Jian Yang
High-quality solid electrolyte interphases (SEI) are important to advanced sodium-ion batteries, particularly on anode materials. Their large structure strain/stress usually aggravates the rupture and dissolution of the SEI, then degrades the electrochemical performance. Here, sodium vinylsulfonate (SVS) is reported as a model to achieve the polymer incorporation into the SEI by in situ electrochemical polymerization. The sulfonate group in SVS activates the vinyl group and interacts with the other components, enabling the polymer to be a robust and flexible backbone of the SEI. This enhances the mechanical properties and reduces the SEI dissolution, improving the electrochemical performance of anode materials. Using commercial tin microparticles (µ-Sn) as an example, they exhibit a capacity of 516.3 mAh g −1 after 2000 cycles at 4 A g −1 , a record-high performance at high rates. This strategy is also successful in the cases of µ-Bi and µ-Sb. These results are obtained based on commercial microparticles without carbon coating. So, it is believed that it is a new and simple way to improve the electrochemical performance of Na-ion batteries.
危险品化学品经营许可证（带存储）