Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of 3D Printing Methods and Materials for Electrochemical
  Energy Storage   Additive manufacturing has revolutionized the building of materials direct
from design, allowing high resolution rapid prototyping in complex 3D designs
with many materials. 3D printing hasenabled high strength damage-tolerant
structures, bioprinted artificial organs and tissues, ultralight metals,
medicine, education, prosthetics, architecture, consumer electronics,and as a
prototyping tool for engineers and hobbyists alike. 3D printing has emerged as
a useful tool for complex electrode and material assembly method for batteries
and supercapacitors in recent years. The field initially grew from
extrusion-based methods such as fused deposition modelling, and evolved to
photopolymerization printing of intricate composites, while supercapacitor
technologies less sensitive to solvents more often involved material jetting
processes. Underpinning every part of a 3D printable battery and many other
devices is the printing method and the nature of the feed material. Material
purity, printing fidelity, accuracy, complexity, and the ability to form
conductive, ceramic, glassy, or solvent-stable plastics relies on the nature of
the feed material or composite to such an extent, that the future of 3D
printable batteries and electrochemical energy storage devices will depend on
materials and printing methods that are co-operatively informed by the
requirements of the device and how it is fabricated. In this Perspective, we
address the materials and methods requirements in 3D printable batteries and
supercapacitors and outline requirements for the future of the field by linking
existing performance limitations to the requirements of printable energy
storage materials, casing materials and the direct printing of electrodes and
electrolytes. We also look to the future by taking inspiration from additive
manufacturing, to posit links between materials and printing methods to allow
new form factor cells.

2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn