Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Molten Air -- A new, highest energy class of rechargeable batteries   This study introduces the principles of a new class of batteries,
rechargeable molten air batteries, and several battery chemistry examples are
demonstrated. The new battery class uses a molten electrolyte, are quasi
reversible, and have amongst the highest intrinsic battery electric energy
storage capacities. Three examples of the new batteries are demonstrated. These
are the iron, carbon and VB2 molten air batteries with respective intrinsic
volumetric energy capacities of 10,000, 19,000 and 27,000 Wh per liter.

36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph