Table 1.

Comparison of design criteria for light-assisted flexible energy storage systems and light-assisted rigid energy storage systems

Design guidelines	Light-assisted rigid energy storage systems		Light-assisted flexible energy storage systems
Core design objectives	Pursuing high photoelectric conversion efficiency, high energy density, and long-term static stability	Balancing optoelectronic performance and mechanical flexibility to ensure consistent performance under deformation and long-term reliability
Base material	Hard substrates (such as glass, ceramics, rigid metal substrates) provide structural support but cannot be deformed	Flexible substrates (such as carbon cloth, polyimide film, polyurethane foam) that combine conductivity and resistance to bending
Light absorbing layer material	Traditional semiconductors (such as TiO2, CdTe) focus on light absorption coefficient and carrier mobility	Flexible light-responsive materials (such as conductive polymers pTTh, two-dimensional materials MoS2, MXene) that combine flexibility and photoactivity
Electrode structure	Rigid layered stacking (such as flat electrode + light-absorbing layer + electrolyte), with a fixed structure and rigid interface connection	3D porous/wrinkled structures (such as nanotube arrays and flower-like nanostructures) reserve deformation space and reduce stress concentration
Electrolyte type	Liquid electrolytes have high ion conduction efficiency but require strict sealing	Gel/solid electrolyte, which combines ionic conductivity and elasticity, prevents leakage, and adapts to deformation
Optoelectronic performance indicators	Focus: Photovoltaic conversion efficiency, energy density, static cycle stability	Focus: Photovoltaic efficiency retention under deformation, light-assisted charge–discharge rate, performance degradation rate after bending cycles
Mechanical performance requirements	No flexible requirements, resistant to static stress	Must withstand multidimensional deformation: bending angle, bending cycle count, compression strain
Package design	Rigid sealed enclosure (such as metal/glass encapsulation), with emphasis on corrosion resistance and long-term sealing	Flexible packaging materials (such as medical tape and waterproof breathable film) must balance sealing properties with deformation adaptability
Typical application scenarios	Stationary energy storage (such as photovoltaic grid-connected storage), static solar charging equipment	Wearable electronics (such as smart bracelets and flexible watches), portable devices (such as foldable solar power banks), and flexible sensor power supplies
Key challenges	Large volume, low integration, difficult to adapt to mobile scenarios; brittle materials can easily lead to structural failure under thermal cycling	Material compatibility (such as the bonding strength between the flexible substrate and the light-absorbing layer); increased charge transport resistance under deformation; performance degradation caused by long-term bending
Key points for performance optimization	Optimize the thickness of the light absorption layer and the contact area of the electrode interface to improve the carrier separation efficiency	Design stress-dispersing structures (such as porous electrodes) and develop self-healing electrolytes to reduce deformation damage to the photoelectric interface