Sodium layered oxides generally suffer from deep-desodiation instability in P2 structure and sluggish kinetics in O3 structure.It will be great to design P2/O3 biphasic materials that bring the complementary merits of both structures.However,such exploration is hindered by the ambiguous mechanism of mate-rial formation.Herein,supported by theoretical simulations and various spectroscopies,we prove that P2/03 biphasic structures essentially originate from the internal heterogeneity of cationic potential,which can be realized by constraining the temperature-driven ion diffusion during solid-state reactions.Consequently,P2/O3 biphasic Na0.7Ni0.2Cu0.1Fe0.2Mn0.5O2-δ with well-designed quaternary composition is successfully obtained,exhibiting much-improved rate capabilities(62 mAh g-1 at 2.4 A g-1)and cycling stabilities(84％capacity retention after 500 cycles)than its single-phase analogues.Furthermore,synchrotron-based diffraction and X-ray absorption spectroscopy are employed to unravel the underlying sodium-storage mechanism of the P2/O3 biphasic structure.This work presents new insights toward the rational design of advanced layered cathodes for sodium-ion batteries.

Xu Gao;Huanqing Liu;Hongyi Chen;Yu Mei;Baowei Wang;Liang Fang;Mingzhe Chen;Jun Chen;Jinqiang Gao;Lianshan Ni;Li Yang;Ye Tian;Wentao Deng;Roya Momen;Weifeng Wei;Libao Chen;Guoqiang Zou;Hongshuai Hou;Yong-Mook Kang;Xiaobo Ji

College of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China;Materials Science and Engineering,Korea University,Seoul 02841,Republic of Korea;Department of Energy and Materials Engineering,Dongguk University-Seoul,Seoul 04620,Republic of Korea;School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing 210014,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;KU-KIST Graduate School of Converging Science and Technology,Korea University,Seoul 02841,Republic of Korea

科学通报（英文版）

[1]Xu Gao;Huanqing Liu;Hongyi Chen;Yu Mei;Baowei Wang;Liang Fang;Mingzhe Chen;Jun Chen;Jinqiang Gao;Lianshan Ni;Li Yang;Ye Tian;Wentao Deng;Roya Momen;Weifeng Wei;Libao Chen;Guoqiang Zou;Hongshuai Hou;Yong-Mook Kang;Xiaobo Ji-.Cationic-potential tuned biphasic layered cathodes for stable desodiation/sodiation)[J].科学通报（英文版）,2022(15):1589-1602

Cationic,potential,tuned,biphasic,layered,cathodes,stable,desodiation,Sodium,oxides,generally,suffer,from,deep,instability,P2,sluggish,kinetics,O3,It,will,be,great,materials,that,bring,complementary,merits,both,structures,However,such,exploration,hindered,by,ambiguous,mechanism,formation,Herein,supported,theoretical,simulations,various,spectroscopies,essentially,originate,internal,heterogeneity,cationic,which,can,realized,constraining,temperature,driven,diffusion,during,solid,state,reactions,Consequently,Na0,7Ni0,2Cu0,1Fe0,2Mn0,5O2,well,designed,quaternary,composition,successfully,obtained,exhibiting,much,improved,rate,capabilities,mAh,cycling,stabilities,capacity,retention,after,cycles,than,single,phase,analogues,Furthermore,synchrotron,diffraction,ray,absorption,spectroscopy,are,employed,unravel,underlying,sodium,storage,This,work,presents,new,insights,toward,rational,advanced,batteries

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