Research for Paper Like Photorechargeable Battery

光可充电电池（PRB）是一种通过阳光或周围光线等光照射储存电能的新设备，它被设想为一种无需充电和馈线的无处不在的电子设备的独立电源。光可充电电极由具有光催化剂的可充电材料组成。电极通过光催化氧化还原反应诱导的离子掺杂或去掺杂而带电。采用可充电碳纤维（CFs）与光催化二氧化钛（TiO_2）复合材料进行了光充电过程的初步研究。本研究的目的是提高对(1)光激发空穴的贡献，(2)CFs与锂离子的反应，(3)CFs表面化学修饰对光充电过程的影响的认识。此外，还开始用导电聚合物聚苯胺（PANi）代替CFs制备类似PRB的光可充电电极。目的1的结果是，光激发的空穴促使锂离子周围的溶剂化物解吸，导致光充电的活化能降低。目的2和目的3通过对电极表面入射光子量、存储电子量和光激发空穴量的定量分析，发现在TiO_2中产生的光激发载流子在光充电过程中损失了70%。这些结果表明，提高PRB性能的关键是减少TiO_2与充电材料界面处的光激发载流子损耗。在TiO_2/PANi电极上，通过纳米级TiO_2与PANi的复合，可使TiO_2/CFs的光充放电量大幅提高100倍。这是因为TiO_2/PANi纳米复合材料在TiO_2和PANi之间有巨大的接触面积。这些结果表明，提高PRB性能的关键是减少光催化剂与充电材料界面处的光激发载流子损失。

Aphotorechargeable battery (PRB)is a new device that can store electric energy by photoirradiation such as sunlight or surrounding light The PRB is supposed for a standalone power supply for ubiquitous electronics without electric charging and feeding wires. The photorechargeable electrode is composed of rechargeable materials with photocatalysts. The electrode is charged by ion doping or de-doping induced by photocatalytic redox reactions. For a primary study for photocharging processe, a composite of photocatalytic TiO_2 and rechargeable carbon fibers (CFs) was used. The purpose of this study is to improve the understanding of (1) the contribution of photoexcited holes, (2) the reaction between CFs and Li-ion and (3) the effect of chemical modification of CFs surface on photocharging process. Further, photorechargeable electrode using conducting polymer polyaniline (PANi) instead of CFs had been started to fabricate paper like PRB.The result for purpose 1 is that the photoexcited holes prompt desorption of solvates around Li-ions resulting in reduction of activation energy for photocharging. For purpose 2 and 3, seventy percent of the photoexcited carriers generated within TiO_2 was lost in photocharging process from quantitative analysis for amount of incident photons, stored electrons and photoexcited holes on electrode surface. These results show the key to improve the performance of PRB is to reduce the photoexcited carrier loss that is supposed to occur at interface between TiO_2 and recharging material.On TiO_2/PANi electrode, photocharged quantity was drastically increased up to 100 times to one of TiO_2/CFs by composing TiO_2 and PANi in nano-level. This is because TiO_2/PANi nanocomposite has huge area of contact between TiO_2 and PANE These results show the key to improve the performance of PRB is to reduce the photoexcited carrier loss that is supposed to occur at interface between photocatalyst and recharging material.