In-situ construction of barium-induced cathode electrolyte interphase to enable mechanostable high-performance zinc-ion batteries

Vanadium-based compounds with open frameworks are recently the subject of intensive research as cathodes for aqueous zinc-ion batteries (AZIBs) with the advantages of high safety and high energy density. However, the spontaneous vanadium dissolution from a cathode and the formation of by-products in aqueous electrolytes are challenging issues that must be addressed as they cause substantial capacity degradation and inadequacy in cycle life. Here, we develop an efficient way to suppress vanadium dissolution via an in-situ formed cathode electrolyte interface (CEI) by incorporating barium ions in the vanadium framework. Such barium ions increase the interlayer structure and act as a sacrificial agent to form an in-situ BaSO4 CEI that reduces vanadium dissolution while enhancing the diffusion kinetics. As a cathodic active material, Ba–V6O13 nanobelts show a specific capacity of 305 mAh g−1 at 0.1 A g−1 and an energy density of 213 Wh/kg, offering excellent reversible capacity retention of 99.94% per cycle. Besides, it operates stably even after physically cutting the device and exhibits excellent interfacial stability. This work presents an innovative strategy to accelerate the commercialization of safe, flexible AZIBs.