INSIGHTS | PERSPECTIVES
PHOTO: KIM TAYLOR/MINDEN PICTURESscience.org SCIENCEparticle homogeneity for battery materials
has been well realized in commercial bat-
teries. In some cases, a mixture of particles
with different sizes is purposely packed into
electrodes to increase the electrode den-
sity, provided that the particles are smaller
than the critical size beyond which cracking
would occur ( 4 , 5 ). In academic research,
however, there are often considerable varia-
tions in the size, shape, and surface prop-
erties of the same materials being used by
industry, which can lead to inconsistent
findings. Li et al. highlight the value of se-
lecting materials with particle-level consis-
tency for application-oriented research.
The contact between active particles and
carbon, as well as the material consistency
of the porous electrode itself, affect the ca-
pacity and cycle life of batteries. Research
efforts using field-guided self-assembly ( 6 ),
freeze-drying ( 7 ), or printing technologies
( 8 ) to gauge the electrode-level structure
ordering are possible solutions if the po-
rosity of electrodes can be better controlled
and monitored. The electrochemical per-
formance of a battery is determined by the
electrode that’s the weakest link. When as-
sessing cathode (or anode) materials, the
corresponding anode (or cathode) must
also be sufficiently stable that the observed
battery performance is not muddled by un-
wanted discrepancies.
In the future, it would be of great in-
terest to develop an integrated approach
for studying all the different components
of a battery. For example, a carbon addi-
tive in positive electrodes is usually only
about 2% by weight but establishes the en-
tire conductive carbon framework for elec-
trodes ( 3 ). Similarly, the distribution of the
very limited amount of electrolyte in a bat-
tery plays an equally outsized role in bat-
tery performance, specifically, in how ions
move within the electrodes. A fundamental
understanding and large-set data analysis
of the dynamics of the particulate system
in battery electrodes can help guide more
refined battery materials and electrode
manufacturing in the future, which will
only become more relevant as the world
gradually moves away from fossil fuel de-
pendency. j
REFERENCES AND NOTES
- J. Li et al., Science 376 , 517 (2022).
- J. Xiao et al., J. Electrochem. Soc. 169 , 010524
(2022). - Y. Bi et al., J. Electrochem. Soc. 169 , 020521 (2022).
- Y. Bi et al., Science 370 , 1313 (2020).
- H. Kim et al., Angew. Chem. Int. Ed. 49 , 2146 (2010).
- D. Wang et al., ACS Nano 4 , 1587 (2010).
- H. Shen et al., ACS Appl. Mater. Interfaces 12 , 3494
(2020). - T. S. Wei et al., Adv. Mater. 30 , 1703027 (2018).
10.1126/science.abo7670A s in mammals, honey bee motivation for
wanting rewards is modulated by dopamine
By Jair E. Garcia^1 and Adrian G. Dyer1,2T
he ability to experience pleasure or
displeasure is created by the brain and
therefore has a physiological compo-
nent ( 1 ). In 1872, based on his observa-
tions of humans and animals, Charles
Darwin proposed that evolution may
select affective reactions that shape behav-
ior, and thus individual fitness^ ( 2 ). Affective
neuroscience in mammals searches for
mechanistic explanations that underpin the
experience of liking or disgust ( 1 ). Recently,
the role of dopamine was reevaluated, show-
ing that it is an important neuromodulator
for wanting rather than liking rewards ( 3 ).
On page 508 of this issue, Huang et al. ( 4 )^
show that regulation of the neurotransmitter
dopamine is also an important component
of the motivation of wanting in honey bees
(Apis mellifera). This suggests that the fit-
ness benefits of a motivation wanting system
regulated by dopamine are likely to be con-served and may explain behavior in a wide
range of animals.
In humans and other mammals, analo-
gous brain circuitry is activated by the
wanting or desire for a reward ( 1 ). For ex-
ample, different reward types such as food,
sex, addictive drugs, and even various forms
of experienced artwork show evidence of
stimulating a brain network that includes
the prefrontal cortex, ventral pallidum, and
amygdala of the primate brain in a similar
manner. Additionally, common mammalian
brain structures, such as the amygdala in
rodents ( 3 ), also show activation to wanting
a reward ( 5 ). This suggests a potential com-
mon reward network of interacting brain re-
gions that underpin rewarding experiences.
An important component of such a reward
system is the regulation of dopamine, which
helps modulate incentive motivation, the
wanting for certain rewards.
Honey bees are an important comparative
species for how brains learn, and together
with other insect models, such as the com-
mon fruit fly (Drosophila melanogaster), are
a test bed to investigate what might be the
minimum brain structures required for infor-(^1) BIDs Lab, School of Media and Communication, RMIT
University, Melbourne, VIC, Australia.^2 Department of
Physiology, Monash University, Clayton, VIC, Australia.
Email: [email protected]; [email protected]
NEUROSCIENCE
Why do animals want
what they like?
Honey bees initiating dance language experience an increased concentration of dopamine, indicating the
presence of a wanting system in insects that is analogous to that observed in mammals, including primates.
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