Eye Tear Activated Mg-Air Battery Driven By Natural Eye Blinking For Smart Contact Lenses

Smart, adaptive contact lenses (SCLs) are amongst the most anticipated, next-generation, standalone medical devices. SCLs require the integration of thin microelectronic components, tunable lenses, and micro-power sources onto a common non-planar substrate. Here, we report a miniaturized, sliding metal-air electrochemical micro-battery driven by natural eye blinking motion that can be integrated with an SCL platform as a source of electrical energy. The metal-air battery (3⋅8 mm2) consists of a Mg anode and a Pt cathode. The electrolyte of the battery is the eye-tear liquid and is introduced to the battery structure during the natural eye-blinking cycle, which activates the battery. The open-circuit voltage across the eye-tear activated metal-air battery (ETMAB) was measured to be 2.2 V and the maximum specific capacity of 3561 mA h g−1 was obtained at a discharge current density of 5 mA·cm−2. Impedance matching analysis exhibits the maximum generated power density of 1.3 mW·cm−2 at the load of 740 Ω.