Recent progress and perspectives on cation disordered rock-salt material for advanced Li-ion batteries

Abstract

During the past decades, the utilization of Li-ion batteries offered the benefit of high energy and power density and can be used in a variety of applications, including the electrical...

Crystallography of Active Particles Defining Battery Electrochemistry

“…This structural type has been thoroughly reviewed. [88,89] More recent literature has looked at the impact of cation variation, both transition metals [90] and the active ion [91] and focused on overcoming the inherently low charging rates of the percolation channels. [92] Perovskite structured min-erals have traditionally been used for photo voltaic cells due to their ability to release electrons when irradiated by solar light, however, they are now being more closely researched for their potential as electrode active materials in rechargeable batteries.…”

Realising higher capacity and stability for disordered rocksalt oxyfluoride cathode materials for Li ion batteries

“…Electrochemical energy storage systems such as Li ion batteries (LIBs) are attractive for electric transportation and storing electrical energy generated by intermittent renewable sources. 1 The ever-growing demand on these applications requires LIBs to achieve higher capacities, lower costs and longer cycle lives. Within the LIB cell, the cathode material is one of the main factors that limits the capacity and dominates the battery costs.…”

“…6 For decades, cation disordering, i.e., mixing of the Li and transition metals (TMs) atoms in the lattice sites, has been considered to limit Li + ion diffusion. 1…”

“…Here, Mn as the redox centre and Ti as the d 0 element are selected for the DRX materials as both Mn and Ti are significantly more abundant (0.1% and 0.6% of the Earth's crust, respectively) 28 than Ni and Co (0.01% and 0.003% of the Earth's crust, respectively) present in the conventional layered cathode materials, 29 and Ti has more favourable effects on Li + percolation when coupled with Mn due to its size for the DRX materials. 1 Three scalable experimental approaches of F substitution with O, reducing particle size and C coating on the particle surface are used to improve the electrochemical performance of the DRX materials. Replacing some of O 2− with F − allows charge compensation with more freedom to tune the stoichiometry of cations such as minimising the level of redox inactive Ti 4+ and increasing the Li + content to increase capacity.…”

Kinetics of Li Transport in Vanadium-Based Disordered Rocksalt Structures

“…However, the development of the so-called zero-transition-metal (0-TM) percolation theory facilitated the design of disordered rocksalt materials with improved Li + transport properties. , The 0-TM percolation theory , was developed based on the concept of octahedral Li occupancy and the tetrahedral site hop (TSH) diffusion mechanism . In this mechanism, a Li + migrates from an octahedral site to an adjacent (edge-sharing) octahedral site via an intermediate tetrahedral site without any TM in the neighboring face-sharing octahedral site (0-TM channel). , According to the 0-TM percolation theory, Li + in a disordered structure can percolate if there is sufficient Li (an excess beyond the 1:1:2 Li/TM/O ratio of typical ordered rocksalt cathodes) to form low-barrier percolating 0-TM diffusion networks. , As disordered rocksalt structures with Li-excess (DRX) materials can be designed with a broader range of elements, ,− the insights gained from the 0-TM percolation theory have provided valuable guidelines for the battery community. This has led to the development of cobalt-free and nickel-free DRX cathode materials capable of delivering specific energies up to 1000 Wh/kg. , …”