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With speeding up development of 5 G chips, high-efficient thermal structure and precise management of tremendous heat becomes a substantial challenge to the power-hungry electronics. Here, we demonstrate an interpenetrating architecture of electrocaloric polymer with highly thermally conductive pathways that achieves a 240% increase in the electrocaloric performance and a 300% enhancement in the thermal conductivity of the polymer. A scaled-up version of the device prototype for a single heat spot cooling of 5 G chip is fabricated utilizing this electrocaloric composite and electromagnetic actuation. The continuous three-dimensional (3-D) thermal conductive network embedded in the polymer acts as nucleation sites of the ordered dipoles under applied electric field, efficiently collects thermal energy at the hot-spots arising from field-driven dipolar entropy change, and opens up the high-speed conduction path of phonons. The synergy of two components, thus, tackles the challenge of sluggish heat dissipation of the electroactive polymers and their contact interfaces with low thermal conductivity, and more importantly, significantly reduces the electric energy for switching the dipolar states during the electrocaloric cycles, and increases the manipulable entropy at the low fields. Such a feasible solution is inevitable to the precisely fixed-point thermal management of next-generation smart microelectronic devices.

Ba­(Hf x Ti1–x )­O3 ferroelectric ceramics were prepared by a conventional solid-state reaction process, and the correlation of structure, dielectric, ferroelectric, and electrocaloric properties were studied. The consequences indicated that the T C of Ba­(Hf x Ti1–x )­O3 ceramics decreased, while T T–O and T O–R increased with the increase of hafnium content. Large electrocaloric effect values of 1.64 K (117 °C) and 1.21 K (76 °C) were observed for Ba­(Hf x Ti1–x )­O3 with x = 0.05 compositions. And, corresponding electrocaloric coefficients respectively were 0.33 and 0.24 K·mm·kV–1. In addition, compared with the second-order phase transition region, larger electrocaloric coefficients (ΔT f /ΔE ≥ 0.19 K·mm·kV–1) were obtained in the first-order phase transition region for all compositions. Meanwhile, the maximum values of electrocaloric coefficients ΔT f /ΔE = 0.38 K·mm·kV–1 was achieved in a smaller electric field for Ba (Hf x Ti1–x )­O3 with x = 0.03 compositions.

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Multi-functional electronic skin is of paramount significance for wearable electronics in health monitoring, medical analysis, and human-machine interfacing systems. In order to achieve the function of natural skin, mechanical sensing with high sensitivity is an important feature of electronic skin. Inspired by the spinosum structure under the skin, herein, we fabricate a new capacitive pressure sensor with two-dimensional transition-metal carbides and nitrides (MXene) and ferroelectric polymer (P(VDF-TrFE-CFE)) as an active layer and micropatterned Cr-Au deposited on polydimethylsiloxane as flexible electrodes. Such a method is facile, effective, easily operated, and low-cost. The device design provides great capacitive change as a consequence of large deformation under pressure. Benefiting from the randomly distributed microstructure and high dielectric constant of the active layer, the device demonstrates high sensitivity with great linearity (16.0 kPa−1 for less than 10 kPa), that is, a low detection limit of 8.9 Pa, and quick response. A series of dynamic physiological signals, including typing, knuckle motion, and voice recognition can be facilely detected, making it a competitive candidate in the field of wearable electronics.