Research for Paper Like Photorechargeable Battery

光充电电池（PRB）是一种利用太阳光或环境光等光辐射来储存电能的新型装置，它是一种不需要充电和馈电线的独立电源，可广泛应用于各种电子设备。光可充电电极由具有光催化剂的可充电材料组成。通过光催化氧化还原反应诱导的离子掺杂或去掺杂使电极带电。采用光催化剂TiO_2与可充电碳纤维复合材料对光充电过程进行了初步研究。本研究的目的是提高对（1）光激发空穴的贡献，（2）碳纤维与锂离子之间的反应以及（3）碳纤维表面化学修饰对光充电过程的影响的认识。此外，使用导电聚合物聚苯胺（PANi）代替CF的光充电电极已经开始制造像PRB的纸。目的1的结果是光激发的空穴促使Li离子周围的溶剂化物脱附，导致光充电的活化能降低。对目的2和目的3，通过对电极表面的入射光子、存储电子和光激发空穴的定量分析，发现在光充电过程中，70%的光激发载流子在TiO_2中损失。结果表明，提高PRB性能的关键是降低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，TiO_2与PANi纳米复合后，光荷电量比TiO_2/CFs提高了100倍。这是因为TiO_2/PANi纳米复合材料在TiO_2和PANE之间有很大的接触面积。这些结果表明，改善PRB性能的关键是减少光催化剂和充电材料之间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.