The rapid development of smart and multifunctional electronics poses significant challenges to design new smart energy storage and conversion devices that can self-regulate according to environmental changes while effectively providing stable and long-lasting output in a reliable

The rapid development of smart and multifunctional electronics poses significant challenges to design new smart energy storage and conversion devices that can self-regulate according to environmental changes while effectively providing stable and long-lasting output in a reliable manner. However, several issues, including complex device configuration, low sensitivity, and safety, often limit the practical application of these devices. In addition, complex external environments and multi-level applications also strongly require smart devices to differentiate between multiple stimulus types in real time. Therefore, it is of great significance to achieve multi-functional integration of energy storage and conversion equipment.

Recently, Institute of Chemistry, Chinese Academy of Sciences Professor Li Yuliang and Professor Huang Changshui prepared a smart solid magnesium-humidity battery (SMB) with graphene nanosheet array that responds to continuous humidity and sunlight. The integrated battery is based on a new concept of chemical bond conversion on the surface of graphene nanosheet arrays, in which the array is obtained by in-situ growth on 3D melamine sponge (GDY/MS). GDY's unique structure, excellent catalytic and semiconductor properties give GDY/MS some outstanding features in capturing and transferring water molecules, catalyzing HER and utilizing solar energy, which makes GDY/MS a new generation cathode for high-performance smart SMBs. Research shows that the performance of GDY/MS-based smart SMB (GSMB) can be continuously adjusted by humidity and sunlight. GSMB shows a clear positive correlation between open circuit potential (OCP) and humidity, while the natural band gap of GDY allows it to further act as a photoelectrode to capture light and generate photoelectrons. Therefore, the GSMB can be used as a self-powered humidity monitor with its ultra-fast response time of 0.24 seconds, recovery time of 0.16 seconds, and sensitive breathing sensing performance (36600%). Overall, this simple and efficient battery preparation strategy represents the future direction of self-powered devices, smart electronic devices, and smart battery integration.

Article highlights:

. This work prepares a hybrid structural material GDY/MS by achieving controllable in-situ growth of emerging carbon isotope graphene (GDY) nanosheet arrays on a three-dimensional melamine sponge (MS) skeleton, and directly uses it as a multifunctional cathode to prepare continuously responsive solid magnesium-humidity batteries (SMB).

. GDY/MS-based SMB (GSMB) is composed of magnesium foil in direct contact with GDY/MS. Research shows that the prepared GDY/MS can be used as a moisture-sensitive unit, catalyst and photoelectrode at the same time. GSMB shows a significant positive correlation between open circuit potential (OCP) and humidity. When the relative humidity is 90%, the OCP can reach a maximum value of ~1.4 V, while the energy density is 411.0 mWh g⁻¹. It is worth noting that the natural band gap of GDY allows it to further act as a photoelectrode to capture and utilize light to generate photoelectrons, thereby increasing the output potential , thus the output potential is significantly increased by 0.13 V.

. The GSMB can be used as a self-powered humidity monitor and shows ultra-fast response time and sensitive breath sensing performance. This humidity battery with smart energy management mode can be used as a self-powered dual-function sensor for real-time monitoring of human respiration, optical sensors, and photovoltaic energy systems.

Fig.1 Material preparation and characterization

Fig.2 Performance of GDY/MS when directly used as SMB cathode

Fig.3 Photoresponse behavior of GSMB

Fig.4 The feasibility of GSMB as a self- power supply system to convert humidity into electrical signals

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Original link:

https://doi.org/10.1021/jacs.2c11409

Source: Frontiers of Polymer Science