Fig. 4
Electrochemical performance of V-Mn AR-PIMBs. a Representative CV curves for single electrode of KxV2O5 (x = 0.25) anode and KxMnO2 (x = 0.23) cathode supported by nanoporous gold current collector in the voltage window of −0.8 to 0 and 0–0.8 V at a scan rate of 50 mV s−1 in 0.5 M K2SO4. b CV curves at various scan rates for aqueous V-Mn AR-PIMBs that are constructed with KxV2O5 and KxMnO2 on nanoporous gold current collectors as anode and cathode. Voltage window is extended to 1.6 V in aqueous electrolyte of 0.5 M K2SO4. c Stack capacity of aqueous V-Mn AR-PIMBs at various scan rates, comparing with previously reported rechargeable aqueous alkaline-metal-ion batteries, such as K+-ion batteries with carbon-encapsulated Fe3O4 nanorod array anode and carbon nanotube film cathode in 3 M KOH electrolyte (Fe–C PIBs)56, Li+-ion batteries with Bi2O3 anode, and LiMn2O4 cathode in a mixed electrolyte of Li2SO4 and LiCl (Bi–Mn LIBs)57, and symmetric Na+-ion batteries of biphase cobalt–manganese oxide nanosheets in 0.1 M Na2SO4 (CoMn–CoMn SIBs)21. d Comparison of self-discharge performance for aqueous V-Mn AR-PIMBs with aqueous Bi–Mn LIBs57, LiFePO4//Mo6S8 (Fe–Mo) LIB, and Zn//polyaniline Zn2+-ion battery (Zn–PANI ZIB)58. e Cycling stability of aqueous V-Mn K+-ion microbatteries at the scan rate of 500 mV s−1. Inset: Typical CV curves at different cycles. f Ragone plot comparing stack energy and power densities of V-Mn AR-PIMB with commercially available 4 V/500 μAh Li thin-film battery, 2.75 V/44 mF commercial activated carbon supercapacitors (AC-SC)9,14, Fe–C PIB56, carbon fiber supported Fe3O4//NiO (Fe–Ni) PIB, Na0.44MnO2//NaTi2(PO4)3 (Mn–Ti) SIB28, Li1.1Mn2O4//LiTi2(PO4)3 (Mn–Ti) LIB and CoNi(OH)2//Zn (CoNi-Zn) ZIB59, as well as onion-like carbon-based microsupercapacitors (onion-like carbon MSC)9
