Tuning LiMnO-Like Domain Size and Surface Structure Enables Highly Stabilized Li-Rich Layered Oxide Cathodes.

Severe capacity/voltage fading still poses substantial obstacles in the commercial applications of Li-rich layered oxides, which stems from the aggregation of LiMnO-like domains and unstable surface structure. Here, we report highly stabilized Co-free LiNiMnO with uniformly dispersed LiMnO-like domains and a protective rock-salt structure shell by reducing the oxygen partial pressure during high-temperature calcination. Experimental characterizations and DFT calculations reveal that the uniformly dispersed and small-sized LiMnO-like domains suppress the peroxidation of lattice oxygen, enabling highly reversible oxygen redox and excellent structural stability.

Structural transformation and electrochemical properties of a nanosized flower-like R-MnO cathode in a sodium battery.

High-energy density and low-cost sodium-ion batteries are being sought to meet increasing energy demand. Here, R-MnO is chosen as a cathode material of sodium-ion batteries owing to its low cost and high energy density. The structural transformation from the tunnel R-MnO to the layered NaMnO and electrochemical properties during the charge/discharge are investigated at the atomic level by combining XRD and related electrochemical experiments.

Cr-Doped FeCrF·0.33HO Nanomaterials as Cathode Materials for Sodium-Ion Batteries.

Due to the high theoretical specific capacity and low cost, FeF·0.33HO has become one of the potential choices of cathode materials for sodium-ion batteries. However, the poor intrinsic conductivity limits its practical applications.

FeP/C Composites as an Anode Material for K-Ion Batteries.

Owing to their natural abundance, the low potential, and the low cost of potassium, potassium-ion batteries are regarded as one of the alternatives to lithium-ion batteries. In this work, we successfully fabricated a FeP/C composite, a novel electrode material for PIBs, through a simple and productive high-energy ball-milling method. The electrode delivers a reversible capacity of 288.

A Cobalt-Free Li(Li Ni Fe Mn )O Cathode with More Oxygen-Involving Charge Compensation for Lithium-Ion Batteries.

High-energy-density and low-cost lithium-ion batteries are sought to meet increasing demand for portable electronics. In this study, a cobalt-free Li(Li Ni Fe Mn )O (LNFMO) cathode material is chosen, owing to the reversible anionic redox couple O /O . The aim is to elucidate the Fe-substitution function and oxygen redox mechanism of experimentally synthesized Li(Li Ni Fe Mn )O by DFT.

A Cobalt-Free Li(Li Ni Fe Mn )O Cathode for Lithium-Ion Batteries with Anionic Redox Reactions.

Lithium-rich, Mn-based layered oxides Li MnO -LiMO (M=Ni, Co) have been considered as promising cathode candidates owing to their high capacity. However, the resources shortage and high price of cobalt make it imperious to substitute cobalt with other high-abundance elements. Here, we synthesized a low-cost, cobalt-free, Fe-substituted oxide material, Li(Li Ni Fe Mn )O .

Chemical anisotropies of carbon nanotubes and fullerenes caused by the curvature directivity.

The directional-curvature theory is developed as a rational basis for the strain energy and the chemical reactivity in single-walled carbon nanotubes (SWCNTs) and fullerenes. The directional curvature KD and its mean KM, derived from this theory, cover the overall curvatures of their bonds and atoms and break through the limitations of the pyramidalized-angle thetap approach, which is only available to atomic curvature. The directional-curvature theory demonstrates that KD and KM depend directly on the strain or reactive binding energies of the bonds and atoms and that there is approximate curvature conservation in SWCNTs and fullerenes.