Suppressing Jahn–Teller distortion in V2O5 /MnV2O6 heterostructures for ultra-stable aqueous zinc-ion batteries

V2O5/MnV2O6 heterostructure suppresses Jahn-Teller distortion via V-O-Mn interface. • In-situ EIS and DRT analysis reveal the dynamic evolution of charge transfer. • Peak of 234.8 mAh g-1, with 94.8% initial retention over 12 000 cycles at 20 A g-1. Aqueous zinc-ion batteries (AZIBs) are increasingly recognized as frontrunners for next-generation energy storage owing to their high safety and cost advantages. Despite these merits, the large-scale implementation of AZIBs is severely constrained by persistent cathode-related problems, including the Jahn-Teller distortion in manganese-based oxides and the vanadium dissolution as well as poor electrical conductivity in vanadium-based oxides. Herein, we report a novel heterostructure (V 2 O 5 -TRZ/MnV 2 O 6 ) constructed from a vanadium-based layered nanosheet precursor by precisely tuning the manganese doping amount and the calcination temperature. The optimized sample (VMn 1 -350) exhibits a unique flower-like morphology assembled from nanowires, with the heterointerfaces to form a stepped energy band gradient. Mn 3+ and V 4+ are both Jahn–Teller active. Upon Mn doping, electron transfer from V 4+ to Mn 3+ generates V 5+ and Mn 2+ , and their synergistic interplay mutually suppresses excessive Jahn-Teller distortion, thereby stabilizing the structure and enabling ultra-long cycling stability. The heterojunction interface establishes an internal electric field that lowers the charge-transfer barrier and enhances charge transport, thereby greatly mitigating polarization during high-rate Zn 2+ (de)intercalation. Triggered by self-activation at 20 A g –1 , the VMn 1 -350 cathode climbs from an initial 170.3 to a peak of 234.8 mAh g –1 , maintaining 161.5 mAh g –1 after 12 000 cycles-a high 94.8% retention relative to the first stable cycle. Combined with ex situ XRD, XPS, in situ EIS, and electrochemical kinetic analyses, the zinc storage mechanism and structural evolution during the charge-discharge process are systematically elucidated. This work demonstrates that the effective inhibition of Jahn-Teller distortion through near-pure Mn 2+ doping, in synergy with the heterostructure and oxygen-vacancy-mediated charge compensation, is crucial for achieving exceptional structural stability and ultra-stable cycling performance in V-based cathode materials designed for aqueous zinc-ion batteries. Download: Download high-res image (325KB) Download: Download full-size image