Deciphering an Abnormal Layered‐Tunnel Heterostructure Induced by Chemical Substitution for the Sodium Oxide Cathode

Abstract

Demands for large-scale energy storage systems have driven the development of layered transition-metal oxide cathodes for room-temperature rechargeable sodium ion batteries (SIBs). Now,a na bnormal layered-tunnel heterostructure Na 0.44 Co 0.1 Mn 0.9 O 2 cathode material induced by chemical element substitution is reported. By virtue of beneficial synergistic effects,t his layered-tunnel electrode shows outstanding electrochemical performance in sodium half-cell system and excellent compatibility with hardc arbon anode in sodium full-cell system. The underlying formation process,c harge compensation mechanism, phase transition, and sodium-ion storage electrochemistry are clearly articulated and confirmed through combined analyses of in situ highenergy X-rayd iffraction and ex situ X-ray absorption spectroscopya sw ell as operando X-rayd iffraction. This crystal structure engineering regulation strategy offers af uture outlook into advanced cathode materials for SIBs.

Recent advance in structure regulation of high‐capacity Ni‐rich layered oxide cathodes

“…Therefore, researchers desire to explore cathode materials with outstanding energy density, which undoubtedly relies on the material breakthroughs. [145][146][147][148][149][150][151] In the last few years, Ni-rich cathodes bring a huge prospect due to high discharging capacity and mass energy density, which is much higher than those of conventional positive materials (LiCoO 2 , LiFePO 4 , etc.). Although Ni-rich cathode materials exhibit an appealing advantage in EV market, it still undergoes unnecessary weaknesses such as inherent volume stress, cathode-electrolyte interface side reaction upon Li + insertion/extraction process.…”

Na+ diffusion mechanism and transition metal substitution in tunnel-type manganese-based oxides for Na-ion rechargeable batteries

“…20,22,23 A beneficial effect of the presence of Cu 2+, has been verified in systems consisting of a mixture of tunnel and layered phases, even if it is clearly difficult to separate the contributions due to the two components of the multi-phase system. 22 At the same time, a positive effect on the cathode electrochemical performances due to the presence of mixture polymorphs in the Na x MnO 2 systems, either layered 24 or tunnel/layered 25,26 phases, has been evidenced also for different compositions. The mechanism and energetics of Na + ion diffusion in the NMO tunnel structure have been the subject of some recent articles based on DFT calculations.…”

Novel P2-type layered medium-entropy ceramics oxide as cathode material for sodium-ion batteries

“…Recently, with the depletion of fossil fuels worldwide and the increasing energy demand, the development of humans in various fields, such as housing, industry, Various positive electrode materials for SIBs, such as Prussian blue analogs, polyanionic compounds, and layered transition metal (TM) oxides have been investigated. The regulation effect on sodium ions in their crystal structure was studied [7][8][9][10][11][12]. P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 (NaNM) is characterized by its high voltage (3.5 V vs. Na/Na + ).…”