nmc cathode optimial particle size effect tap density

Typically, the LFP content in the cathode used for liquid-based systems are in the range of 80–85 wt% 5, 6, 7. Therefore, LFP is used as standard cathode material in the present study. Although a tremendous amount of work has been carried out on solid state electrolytes to improve their ionic conductivities, and chemical, mechanical and electrochemical stabilities within the operating potential window of the electrode 1, 3, less concentration has been paid on the engineering aspects of the cathode for SS-LMBs.Īmong all the cathode materials of lithium-ion battery (LIB) family, LiFePO 4 (LFP) is one of the potential candidates from the application point of view due to its appreciably good theoretical discharge capacity of 170 mAh/g, flat operating potential (3.4 V vs Li +/Li), excellent reversibility, low cost, environmental benignity and high thermal and chemical stabilities 4. In spite of this huge prospect, a rapid commercialization of SS-LMBs is still hindered due to issues such as their low ionic conductivity (presence of all solid components in the cell), low discharge capacity at higher current rates and poor cycle life 1, 2. In addition to high energy density, the SS-LMBs can also assure high safety when compared to the conventional LIBs having flammable organic solvents 1. This is based on the fact that the lithium anode in SS-LMBs can reach ultra-high theoretical specific capacity (3860 mAh g -1), low density (0.53 g cm -3) and lowest electrochemical potential (−3.04 V vs SHE). Therefore, there is renewed interest in using pure lithium metal as anode, which necessitates the adaptation of electrolytes to mechanically stable solid-state electrolytes as well as cathodes towards all solid-state lithium metal batteries (SS-LMBs) 1.

When the current rate was increased to 2C, the electrode still delivered high discharge capacity of 82 mAh g -1 even after 500 cycle, which indicates that the optimum cathode formulation is one of the important parameters in building high rate and long cycle performing SS-LMBs.Īlthough lithium-ion batteries (LIBs) have achieved impressive success in the past years, the energy density that is gradually approaching the theoretical limit in liquid electrolyte-based systems still cannot meet the actual requirements of electrical energy vehicles. As a result, the optimum LFP cathode composition with solid polymer nanocomposite electrolyte (SPNE) delivered higher initial discharge capacities of 114 mAh g -1 at 0.2C rate at 30 ☌ and 141 mAh g -1 at 1C rate at 70 ☌. The SEM analysis of the resulting calendered electrode shows the formation of non-porous and crack-free structures with the presence of conductive graphite throughout the electrode. In addition, a comparative study on different cathode slurry preparation methods was made, wherein ball milling was found to reduce the particle size and increase the homogeneity of LFP which further aids fast Li ion transport throughout the electrode. Since SS-LMBs require a different morphology and composition of the cathode, we selected LiFePO 4 (LFP) as a prototype and, we have systematically studied the influence of the cathode composition by varying the contents of active material LFP, conductive additives (super C65 conductive carbon black and conductive graphite), ion conducting components (PEO and LiTFSI) in order to elucidate the best ion as well as electron conduction morphology in the cathode.

Therefore, it is necessary to have a cathode with good electron conducting channels to increase the active material utilization without blocking the movement of lithium ions. This arise due to the low intrinsic ionic and electronic transport pathways within the solid components in the cathode during the fast charge/discharge processes. In spite of this potential, their low discharge capacities and poor rate performances limit them to be used as state-of-the-art SS-LMBs. All solid-state rechargeable lithium metal batteries (SS-LMBs) are gaining more and more importance because of their higher safety and higher energy densities in comparison to their liquid-based counterparts.

Nmc cathode optimial particle size effect tap density