Aramid nanofibers (ANFs), with attractive
mechanical and thermal
properties, have attracted much attention as key building units for
the design of high-performance composite materials. Although great
progress has been made, the potential of ANFs as fibrous protein mimetics
for controlling the growth of inorganic materials has not been fully
revealed, which is critical for avoiding phase separation associated
with typical solution blending. In this work, we show that ANFs could
template the oriented growth of β-FeOOH nanowhiskers, which
enables the synthesis of ANFs/β-FeOOH hybrids as composite coatings
for polypropylene (PP) separators in Li–S batteries. The modified
PP separator exhibits enhanced mechanical properties, heightened thermal
performance, optimized electrolyte wettability, and improved ion conductivity,
leading to superior electrochemical properties, including high initial
specific capacity, better rate capability, and long cycling stability,
which are superior to those of the commercial PP separators. Importantly,
the addition of β-FeOOH to ANFs could further contribute to
the suppression of lithium polysulfide shuttling by chemical immobilization,
inhibition of the growth of lithium dendrites because of the intrinsic
high modulus and hardness, and promotion of reaction dynamics due
to the catalytic effect. We believe that our work may provide a potent
biomimetic pathway for the development of advanced battery separators
based on ANFs.