Poly(3,4-ethylenedioxythiophene)–Polystyrenesulfonate-Added Layered Vanadium Oxide Cathode for High-Performance Zinc-Ion Batteries

Rechargeable zinc-ion (Zn2+) batteries are emerging as a promising alternative for lithium-ion batteries. However, the reported cathodes normally suffer from sluggish Zn2+ diffusion kinetics, leading to poor rate performance and inadequate cycle life. Introducing additives is a frequently adopted solution. In this work, poly(3,4-ethylenedioxythiophene)–polystyrenesulfonate (PEDOT:PSS) is introduced as the additive into V2O5·3H2O (P-VO) during its one-step hydrothermal growth. Structural characterization indicates that the introduction of PEDOT:PSS not only expands the interlayer spacing of V2O5, thus facilitating Zn2+ diffusion in V2O5, but also increases the ratio of V4+ to V5+, leading to more O vacancies and improved electrochemical activity accordingly. As a result, the aqueous Zn2+ battery with a P-VO electrode exhibits a high capacity (424.3 mAh g–1 at 0.2 A g–1) and long-term cycle stability of up to 2000 cycles with a capacity retention of 89.4% at 5.0 A g–1.