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Ma et al. Soft Sci 2024;4:26 https://dx.doi.org/10.20517/ss.2024.20 Page 27 of 34

Table 6. Summary of typical LIG-based soft power supply devices
Power supply type LIG composites/substrate Working performance Ref.
Lithium-ion batteries LIG/PI Areal capacity: 280 μA·h·cm -2 [48]
2
Glucose enzymatic biofuel cells AuNP@LIG/PLGA maximum power density: 483.1 μW/cm [71]
TENG LIG/PDMS Power output: 1.2 mW [122]
TENG LIG/PDMS Pressure sensitivity: 7.697 kPa -1 [49]
-2
TENG AgNWs@LIG/PDMS/Ecoflex Power: 2.76 W·m [70]
MSC LIG/Ecoflex Capacity: 790 μF·cm -2 [50]
-2
MSC LIG/PI Areal capacitance: 0.62 mF·cm [31]
LIG: Laser-induced-graphene; PI: polyimides; AuNP: gold nanoparticle; PLGA: poly(lactic-coglycolic acid); TENG: triboelectric nanogenerator;
PDMS: polydimethylsiloxane; AgNWs: silver nanowires; MSC: micro-supercapacitor.

The 3D LIG electrode modified by conductive PEDOT could improve the electrical conductivity of
electrodes and enhance the capacitance of these planar MSCs [Figure 13H]. The device achieved a specific
capacity of 790 μF·cm at a discharge current of 50 μA·cm . Meanwhile, Shi et al. proposed all-solid-state,
-2
-2
highly integrated LIG-based MSCs with remarkable pattern variety, outstanding performance uniformity,
flexibility, high integration, and exceptional temperature stability . The cyclic voltammetry (CV) tests
[31]
revealed that the fabricated LIG-based MSCs exhibited high robust stability even when they underwent
different bent states from 0° to 180° [Figure 13I]. Furthermore, the developed device showcased remarkable
high-temperature performance by combining thermally stabile PI substrates with high-temperature stable
ionic liquid electrolytes. Typical LIG-based soft power supply devices for intelligent healthcare are
summarized in Table 6.

Standalone LIGS E
2
The extensive utilization of soft skin electronics in intelligent healthcare is impeded by challenges on power
supply performance and external devices required for data processing and analysis. To tackle this challenge,
Zhao et al. reported a LIG-based soft and sweat-powered health status sensing and visualization system
(HSSVS), which was composed of four sweat-activated batteries (SABs) as power supply modules, three
kinds of sensors, a microcontroller unit (MCU), and a specifically designed light-emitting diode (LED)
array as a health status visualization component [Figure 14A] . The HSSVS system is powered by
[124]
-1
developed SABs, which achieved a maximum specific capacity of 148.10 mAh·g and powered 120 LEDs for
over 8 h. In addition, the fabricated system could perceive a series of crucial human physiological indicators,
including pH levels, Na concentration in sweat, and skin temperature. Furthermore, the standalone
+
HSSVS, when attached to the skin surface, validated the excellent potential for continuous visualization of
an individual’s health status during exercise.

In addition to LIG-based batteries, researchers have developed standalone soft skin electronics by
integrating LIG-based TENG as an energy collector and MSCs as energy storage. For instance, Zhang et al.
reported a porous LIG-based self-powered, wireless, and wearable sensing platform for intelligent health
management [Figure 14B] . The proposed sensing platform comprised LIG-based TENG for mechanical
[47]
energy harvesting, microsupercapacitor arrays (MSCAs) based on LIG for energy storage, and multimodal
biosensor arrays (including pressure, strain, temperature, ECG, and blood oxygen sensors) for biophysical
signals collection. The power supply based on LIG, which combined TENG with MSCAs to harness
mechanical energy from human motions for charging, demonstrates the capability to drive integrated
biosensors. The developed platform could record pulse waves, strain, temperature, ECG, blood pressure,
and blood oxygen from human skin, the monitoring results displayed in a mobile user interface, paving the
way for intelligent healthcare.