Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the ...Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the Jahn-Teller(JT)effect associated with Mn-ion,the cathode exhibits poor structural stability.Herein,we propose a strategy to enhance structural stability by introducing robust metal-oxygen(M-O)bonds,which can realize the pinning effect to constrain the distortion in the transition metal(TM)layer.Concurrently,all the elements employed have exceptionally high crustal abundance.As a proof of concept,the designed K_(0.5)Mn_(0.9)Mg_(0.025)Ti_(0.025)Al_(0.05)O_(2)cathode exhibited a discharge capacity of approximately 100 mA h g^(-1)at 20 mA g^(-1)with 79%capacity retention over 50 cycles,and 73%capacity retention over 200 cycles at 200 mA g^(-1),showcased much better battery performance than the designed cathode with less robust M-O bonds.The properties of the formed M-O bonds were investigated using theoretical calculations.The enhanced dynamics,mitigated JT effect,and improved structural stability were elucidated through the in-situ X-ray diffractometer(XRD),in-situ electrochemical impedance spectroscopy(EIS)(and distribution of relaxation times(DRT)method),and ex-situ X-ray absorption fine structure(XAFS)tests.This study holds substantial reference value for the future design of costeffective Mn-based layered cathodes for PIBs.展开更多
基金Foundation item:supported by Science and Technology Foundation of Shanghai Higher Education(01D01-2)and the Foundation of Ministry of Education for Core Teachers of Higher Education.
基金financially supported by the National Natural Science Foundation of China(NSFC)(52274295)the Natural Science Foundation of Hebei Province(E2021501029)+3 种基金the Fundamental Research Funds for the Central Universities(N2423051,N2423053,N2302016,N2423019,N2323013,N2423005)the Science and Technology Project of Hebei Education Department(QN2024238)the Basic Research Program Project of Shijiazhuang City for Universities Stationed in Hebei Province(241790937A)the Science and Technology Project of Qinhuangdao City in 2023.
文摘Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the Jahn-Teller(JT)effect associated with Mn-ion,the cathode exhibits poor structural stability.Herein,we propose a strategy to enhance structural stability by introducing robust metal-oxygen(M-O)bonds,which can realize the pinning effect to constrain the distortion in the transition metal(TM)layer.Concurrently,all the elements employed have exceptionally high crustal abundance.As a proof of concept,the designed K_(0.5)Mn_(0.9)Mg_(0.025)Ti_(0.025)Al_(0.05)O_(2)cathode exhibited a discharge capacity of approximately 100 mA h g^(-1)at 20 mA g^(-1)with 79%capacity retention over 50 cycles,and 73%capacity retention over 200 cycles at 200 mA g^(-1),showcased much better battery performance than the designed cathode with less robust M-O bonds.The properties of the formed M-O bonds were investigated using theoretical calculations.The enhanced dynamics,mitigated JT effect,and improved structural stability were elucidated through the in-situ X-ray diffractometer(XRD),in-situ electrochemical impedance spectroscopy(EIS)(and distribution of relaxation times(DRT)method),and ex-situ X-ray absorption fine structure(XAFS)tests.This study holds substantial reference value for the future design of costeffective Mn-based layered cathodes for PIBs.
