Power generation through harvesting human thermal energy provides an ideal strategy for self-powered wearable design. However, existing thermoelectric fibers, films, and blocks have small power generation capacity and poor flexibility, which hinders the development of self-powered wearable electronics. Here, we report a multifunctional superelastic graphene-based thermoelectric (TE) sponge for wearable electronics and thermal management. The sponge has a high Seebeck coefficient of 49.2 μV/K and a large compressive strain of 98%. After 10 000 cyclic compressions at 30% strain, the sponge shows excellent mechanical and TE stability. A wearable sponge array TE device was designed to drive medical equipment for monitoring physiological signals by harvesting human thermal energy. Furthermore, a 4 × 4 array TE device placed on the surface of a normal working Central Processing Unit (CPU) can generate a stable voltage and reduce the CPU temperature by 8 K, providing a feasible strategy for simultaneous power generation and thermal management.

Compact solid‐state refrigeration systems that offer a high specific cooling power and a high coefficient of performance (COP) are desirable in a wide range of applications where efficient and localized heat transfer is required. Here, a double‐unit electrocaloric (EC) polymer‐based refrigeration device with high intrinsic thermodynamic efficiency is demonstrated using a flexible EC polymer film with improved performance by doping plasticizer and an electrostatic actuation mechanism. The double‐unit refrigeration device achieves a large temperature span of 4.8 K, which is 71% higher than that of the single‐unit device. A specific cooling power of 3.6 W g−1 and a maximum COP of 8.3 for the cooling device are produced. The surface temperature of a central processing unit (CPU) cooled by an active EC device is 22.4 K lower than that of the CPU cooled in air. The highly efficient and compact EC cooling device demonstrated here not only leapfrogs the performance of existing solid‐state cooling technologies, but also brings solid state cooling closer to reality for a variety of practical applications that require compact or mechanically flexible refrigeration.

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CPU) moved into multi-core, coolers can deal with the chip as a single-site heat source for effective cooling. But the multi-core CPU is packaged as a whole, and the localized overheating site in one core can heat others up. The localized overheating site makes the thermal challenge much more difficult, and it caused more than 55% of all failures in current electronics. [5,6] As operating temperature approaches 70-80 °C, the performance of electronics will degrade by ≈10% for every 2 °C increase. [7] So, the precise cooling technology in integrated circuits has become increasingly a restrictive factor affecting the development of the electronics industry. [8][9][10] Vapor-compression refrigeration systems are bulky, complex, and difficult to scale down to meet the cooling demands of electronic chips. Existing refrigerants also have high global warming potentials, and present an environmental risk upon leakages or improper disposal. Therefore, it is urgent and vital to develop a highly efficient, environmentally friendly, compact, and portable refrigeration device to achieve precise cooling.Solid-state cooling systems, especially caloric-effect-based refrigeration such as the elasto/baro caloric effect, [11] magnetocaloric effect, [12] and electrocaloric (EC) effect, [8,9,[13][14][15] have the advantages of no compressors and conventional liquid or vapor refrigerants, environmental protection, and rapid cooling. The EC refrigeration has been praised for its high coefficient of performance (COP), simple setup, low cost, and feasibility for embedded application in compact integrated circuits. [13] Thus, they can solve the practical cooling requirements of integrated microelectronics that traditional compressor technology is difficult to address. The EC is a reversible adiabatic temperature change (ΔT) and/or isothermal entropy change (ΔS) in dielectric materials induced by an external electric field change (ΔE). [8] Although a large voltage is applied, the generated current and corresponding power consumption are still very small, because of the insulating properties of the EC materials. Therefore, EC refrigeration device exhibits a great application prospect in miniature electronics cooling.Compared to the inherent brittleness of EC multilayer ceramic capacitors, [16,17] the poly(vinylidene fluoride) (PVDF)based ferroelectric polymers have been praised for their light weight, large isothermal entropy change, flexibility, and More than 55% of electronic failures are caused by damage from localized overheating. Up to now, there is still no efficient method for targeted temperature control against localized overheating. Although some existing thermal management devices handle this issue by full coverage cooling, it generates a lot of useless energy consumption. Here, a highly efficient pixel-matrix electrocaloric (EC) cooling device is reported, which can realize a targeted and differential thermal management. The modified poly(vinylidene fluoride-tertrifluoroethylene-chlorofluoroethylene) reaches a large adiabatic te...

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