Tailoring a multifunctional polyglutamic acid–tragacanth gum binder for enhancing the lithium storage performance of red phosphorus anodes

Abstract

Red phosphorus, with its high theoretical specific capacity and safe lithiation potential, is a promising anode for lithium-ion batteries. However, challenges such as significant volume expansion, dissolution of lithium polyphosphides (Li_xpPs), and low electronic conductivity hinder its practical application. In this study, we propose a multifunctional hydrogen-bond enhanced cross-linked binder, polyglutamic acid–tragacanth gum (PGA–TG). The PGA–TG binder not only exhibits strong mechanical properties to inhibit the volume expansion of phosphorus particles but also demonstrates a high affinity for phosphorus, thereby facilitating the capture of soluble Li_xpPs and enhancing the long-cycle performance. Therefore, the PGA–TG-based electrode achieves a lower volume expansion of 19.4% compared with the PVDF-based electrode (233%). Additionally, the PGA–TG-based electrode delivers high reversible capacity of 1575.91 mA h g⁻¹ after 150 cycles at 260 mA g⁻¹ and 1442 mA h g⁻¹ after 280 cycles at 1 A g⁻¹. This work presents a facile and effective binder design strategy to address the multiple challenges associated with phosphorus anodes in lithium-ion batteries.