P2-type nickel-manganese-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs),but their application is limited by initial specific capacity and anion redox instability.Herein,a P2/O3 bip...P2-type nickel-manganese-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs),but their application is limited by initial specific capacity and anion redox instability.Herein,a P2/O3 biphasic Na_(0.67)Ni_(0.33)Mn_(0.6)Cu_(0.05)Mg_(0.07)Ti_(0.01)O_(2)(Ni33Mn60)was prepared by adjusting the Ni/Mn ratio with as Na_(0.67)Ni_(0.23)Mn_(0.65)Cu_(0.05)Mg_(0.07)Ti_(0.01)O_(2)(Ni23Mn65)matrix and is reported to exhibit high initial discharge capacity,cyclability and rate capability.The density functional theory(DFT)calculation and experimental data prove the enhancement of the Mn^(3+)/Mn^(4+)redox process to improve the specific discharge capacity and the P2/O3biphasic structure to optimize the anion kinetics.The synthesized oxide Ni33Mn60 delivers a high initial discharge specific capacity of 140.21 mAh g^(-1),a crucial discharge capacity of 76.07 mAh g^(-1)at 10C,a preferable capacity retention rate of 78.97%after 200 cycles at 5C and cycle stability at high voltages above 4.3V.In situ X-ray diffraction(XRD)and galvanostatic intermittent titration technique(GITT)tests show that Ni33Mn60 has reversible structure evolution and fast Na^(+)diffusion kinetics due to the ion effect and unique P2/O3 biphasic structure,respectively.This work provides a new thought about adjusting matrix ratio for the preparation of P2/O3 biphasic cathode materials for advanced SIBs.展开更多
基金supported by the National Natural Science Foundation of China(20976162,21103149,20906079)Natural Science Foundation of Zhejiang Province,China(R5100266)Significant Science and Technology Project of Zhejiang Province,China(2010C13001)~~
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20201049)China Postdoctoral Science Foundation(No,2022M711724)+2 种基金the Swedish Energy Agency(Nos.P2022-00055 and P2023-00603)STandUP for EnergyMAX IV Laboratory for time on Balder beamline(No.20240704)
文摘P2-type nickel-manganese-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs),but their application is limited by initial specific capacity and anion redox instability.Herein,a P2/O3 biphasic Na_(0.67)Ni_(0.33)Mn_(0.6)Cu_(0.05)Mg_(0.07)Ti_(0.01)O_(2)(Ni33Mn60)was prepared by adjusting the Ni/Mn ratio with as Na_(0.67)Ni_(0.23)Mn_(0.65)Cu_(0.05)Mg_(0.07)Ti_(0.01)O_(2)(Ni23Mn65)matrix and is reported to exhibit high initial discharge capacity,cyclability and rate capability.The density functional theory(DFT)calculation and experimental data prove the enhancement of the Mn^(3+)/Mn^(4+)redox process to improve the specific discharge capacity and the P2/O3biphasic structure to optimize the anion kinetics.The synthesized oxide Ni33Mn60 delivers a high initial discharge specific capacity of 140.21 mAh g^(-1),a crucial discharge capacity of 76.07 mAh g^(-1)at 10C,a preferable capacity retention rate of 78.97%after 200 cycles at 5C and cycle stability at high voltages above 4.3V.In situ X-ray diffraction(XRD)and galvanostatic intermittent titration technique(GITT)tests show that Ni33Mn60 has reversible structure evolution and fast Na^(+)diffusion kinetics due to the ion effect and unique P2/O3 biphasic structure,respectively.This work provides a new thought about adjusting matrix ratio for the preparation of P2/O3 biphasic cathode materials for advanced SIBs.
