Shaikh N.S.Lokhande V.C.Ji T.Ubale S.Mane V.J.Lokhande C.D.Shaikh H.M.Shaikh J.S.Praserthdam S.Sabale S.Kanjanaboos P.Mahidol University2023-06-182023-06-182022-01-01Dalton Transactions (2022)14779226https://repository.li.mahidol.ac.th/handle/20.500.14594/84221In recent years, modern appliances require high energy density with a burst power supply. Hybrid supercapacitors show high performance based on high energy density without compromising power density and stability over thousands of charge-discharge cycles. In this work, the optimized hybrid electrodes using lanthanum-doped hematite (lanthanum-doped iron oxide) noted as 7.5%La-HMT as a negative electrode and hydrous cobalt phosphate (CoPO) as a battery-type positive electrode have been successfully fabricated via a simple hydrothermal method and a facile co-precipitation method, respectively. The 7.5%La-HMT showed excellent electrochemical performance due to doping of rare-earth La3+ metal ions, resulting in improvised active sites and reduction in the equivalent resistance. The 7.5%La-HMT operated at a high potential window (0 to −1.2 V) with an ultra-high specific capacitance (Sp) of 1226.7 F g−1 at 1 A g−1 with capacitance retention of 89.3% over 1000 cycles. CoPO could be operated at a high working window (0 to 0.45 V) with a specific capacity of 121.7 mA h g−1 at a current density of 2 A g−1 with capacitance retention of 85.4% over 1000 cycles. The configured CoPO//KOH//10%La-HMT aqueous hybrid capacitor device (Aq-HSC) could be operated at a potential window of 1.6 V and delivered a maximum energy density (E.D) of 83.6 W h kg−1 at a power density (P.D) of 3.2 kW kg−1 with Sp of 235.0 F g−1 at 2 A g−1 and 89.0% Sp retention over 5000 cycles. The simplicity of the synthesis methods for CoPO and 7.5%La-HMT along with their superior super-capacitive properties make them suitable for advanced electrical devices and hybrid vehicles.ChemistryArticleSCOPUS10.1039/d1dt04164a2-s2.0-851287999351477923435388825