Research for Paper Like Photorechargeable Battery

光电可充电电池(PRB)是一种利用太阳光或周围光线等光能来存储电能的新型器件，它是一种不需要充电和馈线的独立电源，可用于无处不在的电子设备。该光充电电极由带有光催化剂的可充电材料组成。电极由光催化氧化还原反应引起的离子掺杂或脱掺杂充电。将光催化二氧化钛与可充电碳纤维(CFs)复合，对其光充电过程进行了初步研究。本研究的目的是加深对(1)光激发空穴的贡献，(2)CFS与锂离子的反应和(3)CFS表面的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CFS的光充电电极已经开始用于制备类似于PRB的纸张。目的1的结果是，光激发空穴促使Li-离子周围的溶剂解吸，从而降低了光充电的活化能。对于目的2和目的3，通过对电极表面入射光子量、存储电子和光激发空穴的定量分析，发现在光充电过程中，TiO2光激发载流子损失了70%。这些结果表明，降低二氧化钛与充电材料界面处的光致载流子损耗是提高纳米二氧化钛/聚苯胺复合电极性能的关键。在二氧化钛/聚苯胺电极上，通过纳米级的二氧化钛和聚苯胺的复合，使纳米二氧化钛/聚苯胺电极的光电荷量大大增加，达到了二氧化钛/聚苯胺电极的100倍。这是因为二氧化钛/聚苯胺纳米复合材料在二氧化钛和聚苯胺之间有很大的接触面积，这些结果表明，降低光催化剂和充电材料界面处的光激载流子损失是提高PRB性能的关键。

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.