Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A salt water battery with high stability and charging rates made from
  solution processed conjugated polymers with polar side chains   We report a neutral salt water based battery which uses p-type and n-type
solution processed polymer films as the cathode and the anode of the cell. The
specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via
formation of bipolarons in both the p-type and n-type polymers. By engineering
ethylene glycol and zwitterion based side chains attached to the polymer
backbone we facilitate rapid ion transport through the non-porous polymer
films. This, combined with efficient transport of electronic charge via the
conjugated polymer backbones, allowed the films to maintain constant capacity
at high charge and discharge rates (>1000 C-rate). The electrodes also show
good stability during electrochemical cycling (less than 30% decrease in
capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance
of these semiconducting polymers with polar side-chains demonstrates the
potential of this material class for fast-charging, water based electrochemical
energy storage devices.

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The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
18
The categories of this paper are: econ
1
The categories of this paper are: cs