Understanding the effect of an in situ generated and integrated spinel phase on a layered Li-rich cathode material using a non-stoichiometric strategy

Enhanced Electrochemical Capacity of Spherical Co-Free Li1.2 Mn0.6 Ni0.2 O2 Particles after a Water and Acid Treatment and its Influence on the Initial Gas Evolution Behavior

Li-rich layered oxides (LRLO) with specific energies beyond 900 Wh kg^-1 are one promising class of high-energy cathode materials. Their high Mn-content allows reducing both costs and the environmental footprint. In this work, Co-free Li_1.2 Mn_0.6 Ni_0.2 O₂ was investigated. A simple water and acid treatment step followed by a thermal treatment was applied to the LRLO to reduce surface impurities and to establish an artificial cathode electrolyte interface. Samples treated at 300 °C show an improved cycling behavior with specific first cycle capacities of up to 272 mAh g^-1 , whereas powders treated at 900 °C were electrochemically deactivated due to major structural changes of the active compounds. Surface sensitive analytical methods were used to characterize the structural and chemical changes compared to the bulk material. Online DEMS measurements were conducted to get a deeper understanding of the effect of the treatment strategy on O₂ and CO₂ evolution during electrochemical cycling.

In Operando Neutron Scattering Multiple-Scale Studies of Lithium-Ion Batteries

Real-time observation of the electrochemical mechanistic behavior at various scales offers new insightful information to improve the performance of lithium-ion batteries (LIBs). As complementary to the X-ray-based techniques and electron microscopy-based methodologies, neutron scattering provides additional and unique advantages in materials research, owing to the different interactions with atomic nuclei. The non-Z-dependent elemental contrast, in addition to the high penetration ability and weak interaction with matters, makes neutron scattering an advanced probing tool for the in operando mechanistic studies of LIBs. The neutron-based techniques, such as neutron powder diffraction, small-angle neutron scattering, neutron reflectometry, and neutron imaging, have their distinct functionalities and characteristics regimes. These result in their scopes of application distributed in different battery components and covering the full spectrum of all aspects of LIBs. The review surveys the state-of-the-art developments of real-time investigation of the dynamic evolutions of electrochemically active compounds at various scales using neutron techniques. The atomic-scale, the mesoscopic-scale, and at the macroscopic-scale within LIBs during electrochemical functioning provide insightful information to battery researchers. The authors envision that this review will popularize the applications of neutron-based techniques in LIB studies and furnish important inspirations to battery researchers for the rational design of the new generation of LIBs.

A review on the electrochemical reaction of Li-rich layered oxide materials

Lithium-rich layered oxide materials xLi2MnO3·(1 − x)LiMO2 (M = Mn, Co, Ni, Fe, Cr, etc.) as promising cathode candidates for high energy Li-ion batteries have been summarized in this review.

Synthesis and electrochemical characterization of Mg–Al co-doped Li-rich Mn-based cathode materials

A novel synergistic strategy to improve electrochemical performance of Li-rich cathode by co-doping of magnesium and aluminium.

Spinel/Layered Heterostructured Lithium-Rich Oxide Nanowires as Cathode Material for High-Energy Lithium-Ion Batteries

Lithium-rich oxide material has been considered as an attractive candidate for high-energy cathode for lithium-ion batteries (LIBs). However, the practical applications are still hindered due to its low initial reversible capacity, severe voltage decaying, and unsatisfactory rate capability. Among all, the voltage decaying is a serious barrier that results in a large decrease of energy density during long-term cycling. To overcome these issues, herein, an efficient strategy of fabricating lithium-rich oxide nanowires with spinel/layered heterostructure is proposed. Structural characterizations verify that the spinel/layered heterostructured nanowires are a self-assembly of a lot of nanoparticles, and the Li₄Mn₅O₁₂ spinel phase is embedded inside the layered structure. When the material is used as cathode of LIBs, the spinel/layered heterostructured nanowires can display an extremely high invertible capacity of 290.1 mA h g^-1 at 0.1 C and suppressive voltage fading. Moreover, it exhibits a favorable cycling stability with capacity retention of 94.4% after charging/discharging at 0.5 C for 200 cycles and it shows an extraordinary rate capability (183.9 mA h g^-1, 10 C). The remarkable electrochemical properties can be connected with the spinel/layered heterostructure, which is in favor of Li⁺ transport kinetics and enhancing structural stability during the cyclic process.