High-voltage positive electrode materials for lithium-ion batteries

TL;DR: An outlook on lithium ion technology is presented by providing first the current status and then the progress and challenges with the ongoing approaches, and finally points out practically viable near-term strategies.

TL;DR: Tarascon and Assat as mentioned in this paper discuss the underlying science that triggers a reversible and stable anionic redox activity and highlight its practical limitations and outline possible approaches for improving such materials and designing new ones.

TL;DR: An overview of the energy storage devices from conventional capacitors to supercapacitors to hybrid systems and ultimately to batteries is provided, although the focus is kept on capacitive and hybrid energy storage systems.

Abstract: Secondary batteries based on metal anodes (e.g., Li, Na, Mg, Zn, and Al) are among the most sought‐after candidates for next‐generation mobile and stationary storage systems because they are able to store a larger amount of energy per unit mass or volume. However, unstable electrodeposition and uncontrolled interfacial reactions occuring in liquid electrolytes cause unsatisfying cell performance and potential safety concerns for the commercial application of these metal anodes. Solid‐state electrolytes (SSEs) having a higher modulus are considered capable of inhibiting difficulties associated with the anodes and may enable building of safe all‐solid‐state metal batteries, yet several challenges, such as insufficient room‐temperature ionic conductivity and poor interfacial stability between the electrode and the electrolyte, hinder the large‐scale development of such batteries. Here, research and development of SSEs including inorganic ceramics, organic solid polymers, and organic–inorganic hybrid/composite materials for metal‐based batteries are reviewed. The comparison of different types of electrolytes is discussed in detail, in the context of electrochemical energy storage applications. Then, the focus of this study is on recent advances in a range of attractive and innovative battery chemistries and technologies that are enabled by SSEs. Finally, the challenges and future perspectives are outlined to foresee the development of SSEs.

TL;DR: In this paper, Li-rich layered Ni-Mn-Co oxide materials have been extensively studied in the past decade and they have shown much improved overall electrochemical performance compared to the core-only and shell-only samples.

TL;DR: In situ spectroscopic ellipsometry was employed to study the initial stage of SEI layer formation on thin-film LiMn{sub 2}O{sub 4} electrodes as discussed by the authors.

Abstract: Alternative micro-sized LiNi0.5Mn1.5O4 spinels with octahedral structure (showing only one type of {111} crystal face) or chamfered polyhedral structure with extra other faces have been synthesized via a controllable method. A possible growth model, complexing–pyrolyzing-oriented, is also proposed for the formation of chamfered polyhedral LiNi0.5Mn1.5O4 spinel based on the experimental results in this paper. The chamfered polyhedral LiNi0.5Mn1.5O4 can provide a large capacity of 103 mA h g−1 even at a discharge rate as high as 50 C, which is far superior to that of the octahedral structure. Besides, the capacity retentions of the chamfered polyhedral composites are found to be 90.82% at 25 °C after 500 cycles and 90.00% at 55 °C after 200 cycles, which are also better than those of the octahedral composites. These results represent the first experimental evidence for lattice-plane anisotropy in LiNi0.5Mn1.5O4 crystals. Moreover, the pseudo-sphere structure is beneficial for obtaining high volumetric energy density and excellent processability in practical applications. In short, we have revealed for the first time that, through chamfering an octahedron to a pseudo-sphere-like polyhedron rather than doping or coating, a micro-sized LiNi0.5Mn1.5O4 spinel with good compatibility between energy/power density and cycle life can be synthesized successfully without sacrificing other properties.

TL;DR: A unique chemical treatment for the activation of the Li2MnO3 phase of the shell, a high capacity is realized with the Li‐rich shell material and Aberration‐corrected scanning transmission electron microscopy provides direct evidence for the formation of surface Li‐ rich shell layer.