There
is an urgent need to design practical aqueous rechargeable
batteries (ARBs) with high energy density and long cycle life, using
state-of-the-art cathode materials with low toxicity and environmental
friendly nature. In virtue of the stable discharge potential and high
energy density, silver (Ag) presents a huge perspective in the field
of aqueous batteries. Herein, the paradigm of a novel core–shell
Ag@Cu structure in situ Cu porous nanowire array skeleton (Ag@Cu NWA)
is designed as the efficient cathode of an ARB. Benefiting from the
ultrathin metal Ag shell (∼7 nm) and the high-conductivity
metal Cu core, along with the robust porous nanowire framework, the
as-obtained Ag@Cu NWA cathode integrates the features of maximal utilization
of the active material, superior charge transfer, and exceptional
electrolyte accessibility, exhibiting a considerable capacity of 1.79
mA h cm–2 (458 mA h g–1: 92.3%
of theoretical capacity) and remarkable cycling stability (83.6% retention
after 5000 cycles). Furthermore, a well-designed aqueous rechargeable
Ag//Bi full cell is fabricated using the Ag@Cu NWA cathode, achieving
high capacity (1.57 mA h cm–2 at 2 mA cm–2) with excellent rate performance (92.9% at 20 mA cm–2) and an admirable energy density of 16.96 mW h cm–3. This work puts forward a prospective strategy to construct viable
new types of ARB materials based on multimetal nanocomposites, showing
great potential for practical electronic devices.