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TITLE Development of recycling technology for the electrode materials (Li, Co) of lithium ion secondary battery by molten salt processing to improve energy use efficiency
(Joint Program to Promote Technological Development with the Private Sectors)

RITE - TOKYO KOTO LABORATORY in Kawasaki  Heavy Industries, Ltd.

ABSTRACT Making the best use of high reactivity and high thermal stability, which are remarkable advantages of molten salt processing, development for realizing recycling of Li and Co from the oxide electrode material (LiCoO2) of lithium ion secondary battery with high energy use efficiency has been carried out as follows:

1. Reduction conditions of LiCoO2 in molten salt are optimized, and operation parameters required for designing of a bench scale plant are established,

2. Electrolysis conditions to recover Li from Li2O which are generated by the reduction, are optimized, and operation parameters required for designing of a bench scale plant are established,

3. Corrosion data of the structure materials are investigated, and structure materials for molten salt handling equipments are selected. Moreover, the compatibility with molten salt is investigated and the maintenance methods are established, and

4. Finally, a bench scale plant is manufactured. The capacity, the energy use efficiency and the molten salt handling are confirmed by the bench scale test.

The results obtained in the last year are shown below.

(1) Optimization of process conditions
The following process conditions were derived in accordance with the design and manufacture of a 1/25 bench scale plant:

- LiCl molten salt quantity: LiCl/LiCoO2 below 30wt ratio
- Reduction Li quantity: Li/LiCoO2 below 0.4wt ratio
- Reduction reaction time: approximately. 2 hours
- Li electrolysis electrode: Iron
(2)  1/25 bench scale plant design and manufacture

A 1/25 bench scale plant based on the optimized process conditions was designed and manufactured. For primary equipment, a bench scale test apparatus for Li and Co recovery and glove box and gas circulation purification equipment were designed and manufactured.

(3)  1/25 bench scale plant operation test
Reduction reaction processing to recover Co and Li electrolysis processing to recover Li was carried out and accomplished using the 1/25 bench scale plant. In addition, concerning a solution of the issue of upgrading existing equipment for this system, a basket shape for LiCoO2 and electrode specifications were derived and studied.