Lithium rocking-chair cells

The concept of lithium rocking-chair cells or lithium-ion batteries (LiBs) is not new. It has been proposed in the late 1970s by Armand who suggested to use two different intercalation compounds as a positive and negative electrode, in the so-called rocking-chair battery, the lithium ions being transferred from one side to the other [35]. Practically they were demonstrated in the early 1980s [36]. 

For comparison Modern lithium rocking chair cells work at a ceU voltage of 4V over 1000 cycles with energy densities exceeding 100 Wh/kg [698]. 

Beginning in the early 1980s [20, 21] metallic lithium was replaced by lithium insertion materials having a lower standard redox potential than the positive insertion electrode this resulted in a "Li-ion" or "rocking-chair" cell with both negative and positive electrodes capable of reversible lithium insertion (see recommended papers and review papers [7, 10, 22-28]). Various insertion materials have been proposed for the anode of rechargeable lithium batteries,... 

Figure 1. Schematic description of a (lithium ion) rocking-chair cell that employs graphitic carbon as anode and transition metal oxide as cathode. The undergoing electrochemical process is lithium ion deintercalation from the graphene structure of the anode and simultaneous intercalation into the layered structure of the metal oxide cathode. For the cell, this process is discharge, since the reaction is spontaneous.

As a future development, realization of monolithic rocking chair cells may be one option [1]. A common network between the electrolyte and electrode materials would provide a continuous matrix for the lithium cation transfer from the electrode to the electrolyte or vice versa, and would consequently reduce the interfacial charge transfer resistance (Fig. 2.12). 

The crucial factor in this battery is that both electrodes are able to act as hosts for the Li+ ions, and the system has been termed a rocking-chair cell to reflect the fact that the Li ions rock back and forth between the two host materials during charging and discharging. Lithium-ion batteries have applications in, for example, laptop and notebook computers, mobile phones and portable CD players, and have potential use in electric cars. 

With regard to rechargeable cells, a number of laboratory studies have assessed the applicability of the rocking-chair concept to PAN-EC/PC electrolytes with various anode/cathode electrode couples [121-123], Performance studies on cells of the type Li°l PAN-EC/PC-based electrolyte lLiMn20 and carbon I PAN-EC/PC-based electrolyte ILiNi02 show some capacity decline with cycling [121]. For cells with a lithium anode, the capacity decay can be attributed mainly to passivation and loss of lithium by its reaction with... 

Lithium-ion (shuttle-cock, rocking-chair, swing) battery is widely considered as the most advanced power source for consumer electronics and is regarded as the most promising battery technology for a variety of other applications, such as electric vehicles, medicine and space exploration. One of the most critical factors in designing successful Li-ion cell is the choice of... 

The need to develop high rate performance electrodes [116] in advanced batteries, such as rocking-chair (lithium-ion) cells [117], has led to efforts... 

Many of the intercalation batteries being studied now are so-called rocking chair or lithium ion cells, in which both electrodes are lithium intercalation compounds. Thus there is a need for electrodes with a low voltage vs lithium (for the anode) as well as those with a high voltage (for the cathode). Early studies of intercalation compounds for electrodes were part of a search for cathodes, not anodes, and may have passed over materials suitable for anodes. 

As Figure 14 shows, the combination of two lithium insertion materials (characterized by two different potentials of the lithium insertion process) yields a cell—the so-called rocking chair battery , after Armand [105] and Scrosati et al. [106]—in which during discharge lithium ions are released from the anode and travel through the electrolyte toward the cathode without variation in the composition of the... 

For recharge the arrows have to be reversed. This back and forth of the lithium ions is named rocking chair or swing principle. The varieties and specialties of the electrodes and other cell components are investigated as follows. 

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