The urgent demand for renewable energy has attracted widespread interest in polymer‐based thermoelectric materials due to easy fabrication, high flexibility, low toxicity, low thermal conductivity, and great potential in industrial applications. However, the power factors of the polymers are still quite low compared with those of their inorganic counterparts, resulting in a low energy conversion efficiency. Highly conductive carbon materials, including graphene and carbon nanotubes, have recently been incorporated into the polymer matrix through intrinsic chemical intimacy, providing new opportunities to tune the thermoelectric properties. In particular, the characteristic π‐π coupling and other interactions between the two components have contributed to unique mechanisms for better thermoelectric performance beyond the simple rule of mixtures. This paper aims to review the up‐to‐date progress in polymer/carbon nanocomposites along with various compositions and novel synthetic strategies. The salient aspects of this review are characteristic interactions and various mechanisms, which might result in enhanced thermoelectric properties and subsequent potential applications in energy harvesting, wearable electronics, photo‐thermoelectrics, and other devices.

Graphene has been considered as an excellent filler to reinforce ceramics with enhanced properties. However, the uniform dispersion and controlled orientation of graphene sheets in a ceramic matrix have become major challenges toward higher performance. In this paper, we prepared MgO matrix composites with parallel graphene layers through the intercalation of the precursor into expandable graphite. We obtained a high electromagnetic interference (EMI) shielding effectiveness of ~30 dB, due to the multiple reflections and absorptance of electromagnetic waves between the parallel graphene layers. The hardness and strength of the MgO composite were also increased by introducing parallel graphene layers. All these properties suggest that the graphene/MgO composite represents a promising electromagnetic shielding material.

There is an urgent demand of ultrathin high‐performance microwave absorbing materials (MAMs) in the electromagnetic protection field. However, minimizing thickness is challenging mainly due to dielectric mismatch at high permittivity from excessive dielectric loss, leading to strong reflection at 2–18 GHz. Here, a hybrid TaS2/Co(Cp)2 superlattice is fabricated with alternating [TaS2] inorganic layers and [Co(Cp)2] organic layers. Dynamic Ta─Co dipoles offer a unique interfacial polarization relaxation mechanism involving the inversion and rotation of dynamic Ta─Co dipoles. The prolonged relaxation time of limited dynamic Ta─Co dipoles contributes to enhanced dielectric matching at high permittivity, which is essential for ultrathin high‐performance MAMs. Furthermore, the confinement of paramagnetic Co(Cp)2 molecules in the interlayer space of the diamagnetic TaS2 sublattice triggers unexpected ferromagnetism via interfacial magnetic coupling conducive to the improved microwave‐absorbing performance at reduced thickness. Therefore, it presents a 1.271‐mm thick ultrathin absorber that can attenuate up to 99.99% of electromagnetic wave energy with a broad effective absorption bandwidth of 4.05 GHz, thus pushing the limits of thickness of 2D‐based high‐performance MAMs. This paper demonstrates a new strategy toward ultrathin MAMs with tunable and decent electromagnetic loss derived from electrical and magnetic coupling at the atomic scale.