The state transitions of solvated H-Ras protein with GTP were theoretically analyzed through molecular dynamics (MD) simulations. To accelerate the structural changes associated with the locations of two switch regions (I and II), the Parallel Cascade Selection MD (PaCS-MD) method was employed in this study. The interconversions between the State 1 and State 2 were thus studied in atomic details, leading to a reasonable agreement with experimental observations and consequent scenarios concerning the transition mechanism that would be essential for the development of Ras inhibitors as anti-cancer agents. Furthermore, the state-transition-based local network entropy (SNE) was calculated for the transition process from State 1 to State 2, by which the temporal evolution of information entropy associated with the dynamical behavior of hydrogen bond network composed of hydration water molecules was described. The calculated results of SNE thus proved to provide a good indicator to detect the dynamical state transition of solvated Ras protein system (and probably more general systems) from a viewpoint of nonequilibrium statistical thermodynamics.

Introduction Lead Acid Batteries (LAB) are used in various fields, due to its low cost and excellent recyclability. Conventionally, LAB cannot be recharged after over-discharged and its performance is greatly declined. We have found that the above deterioration is causedby the formation of α-PbO2 on the surface of cathode active material β-PbO2 due to the reduction by local cell reaction between β-PbO2 and lead current collector. We also have revealed that the formation of α-PbO2 can be prevented by using gold instead of lead as current collector. In this case, the LAB can be recharged even after either discharging to 0 V or discharging to 0 V followed by 48 h open circuit [1,2]. In the case of carbon, electrode potential does not come out, so we thought that carbon has a role of stopping local cell reaction. We revealed that the LAB using graphite sheet with 5wt% polypropylene as current collector has high resistance to over-discharge [3,4,5]. This LAB can charge-discharge without performance degradation even after full discharge followed by 48 h rest period. In this study, we fabricated composite cathode composed of β-PbO2 as active material and expanded graphite as current collector, in order to get higher performance and ease of fabrication. We investigated performance of the LAB using the composite cathode. Experiment We made various kind of the composite cathode composed of β-PbO2 of 0.18-3.6 g, expanded graphite of 1.8 g and polypropylene of 0.09 g by a pressure molding. We conducted charge-discharge experiments by using the composite cathode. We used two-electrode glass cell for charge-discharge experiments. We used 35 % H2SO4 as electrolyte and lead plate as anode. Composite cathode was processed to 40 mm × 14 mm and the area immersed in sulfuric acid was 10 mm × 14 mm. As the stabilization cycle, we repeated discharge at 0.25 mA for 30 min and charge at 2 mA for 20 min for 20 times, then we conducted charge discharge experiment. Results and discussion After the stabilization cycle, we discharged LAB deep to 0 V and opened the circuit for 48 h, then we resumed charge-discharge cycle. Figure 1(a) shows the charge-discharge characteristics of conventional type LAB using lead plate cathode current collector. Conventional type LAB could not resume charge-discharge cycle after full discharge followed by48 h open circuit. Figure 1(b) shows the case of the LAB using composite cathode. It is indicated that the LAB can resume charge-discharge cycle even after full discharge followed by 48 h open circuit. It is confirmed that the composite cathode made the LAB so durable to over-discharge. Figure 2 shows detailed discharge curve of the LAB using the composite cathode composed of β-PbO2 of 3.6 g, expanded graphite of 1.8 g and polypropylene of 0.09 g. Weight composition of β-PbO2 in this composite cathode is about 65%. The charge rate was 2 mA, and the discharge rate was 0.1 mA, respectively. The flat discharge potential around at 1.6 V was observed. This means that the LAB using the composite cathode has excellent practical performance. It was indicated that the composite cathode made the LAB not only very durable in over discharge but also highly practical for use. Reference [1] T.Iwai, D.Kitajima, S.Takai, T.Yabutsuka and T.Yao, J. Electrochem. Soc. Vol 163, Issue 14, A3087-A3090 (2016) [2] T.Iwai, M.Murakami, S.Takai, T.Yabutsuka and T.Yao, Journal of Alloys and Compounds, Vol 780, 85-89 (2019) [3] T.Yao, H.Okano, T.Iwai, S.Takai, T.Yabutsuka, T.Hosokawa, N.Misaki, K.Kurihara “Positive Electrode for Lead Storage Battery and Lead Storage Battery Using Same” PCT/JP2018/005947 [4] Y.Nakamura, T.Ohkubo, H.Okano, T.Inoue, T.Hosokawa, A.Takeda, T.Iwai, T.Yabutsuka, S.takai and T.Yao, 235th ECS Meeting. Soc. Z01-2143 (2019) [5] Y.Hano, H.Okano, T.Inoue, T. Hosokawa, A.Takeda, T.Iwai, T.Yabutsuka, S.Takai, and T. Yao, PRIME 2020. Soc. Z01-3448 (2020) Figure 1

Introduction Lead Acid Batteries (“LAB”) have been widely used for more than 100 years. LAB cannot be recharged after over-discharged, and its performance is greatly declined. Iwai et al. have found that the above deterioration is caused by the formation of α-PbO2 on the surface of cathode active material β-PbO2 due to the reduction by local cell reaction. They also have revealed that the formation of α-PbO2 can be prevented by using gold or platinum as cathode current collector. At that case, the LAB can be recharged even after over-discharge.[1,2] We revealed, furthermore, that LAB using graphite sheet as cathode current collector also has high resistance to over-discharge.[3] This LAB can charge/discharge without performance degradation even after full discharge followed by 48 h rest period. In order to improve sulfuric acid resistance, we tried to mix four kinds of resin (polyethylene, polypropylene, ethylene propylene copolymer and fluororesin) to the graphite sheet. It is revealed that the weight of graphite sheet did not increase by immersion test into sulfuric acid for more than or equal to 5 wt% polypropylene mix, and that surface electrical resistance of the sheet did not increase for less than or equal to 5 wt% polypropylene mix.[4] We decided to use graphite sheet with 5 wt% polypropylene as cathode current collector. For this LAB, we have investigated long term charge deep-discharge cycle performance including various kinds of rest-period. We also investigated the rechargeablity after 0V discharge followed by various long rest period. Experiment We made the resin-dispersed graphite sheet in order to improve electrolyte repellency compared to normal graphite sheet. We used polypropylene for resin material and dispersed it by 5 wt% into expanded graphite, then we made it into sheet by rolling mill. The heat treatment was preheating at 100℃ for 10 min and then at 180℃ for 10 min to disperse resin evenly. We used two-electrode glass cell for charge/discharge experiments. The cathode active material was prepared by mixing β-PbO2 powder, acetylene black and PTFE at the ratio of 80:15:5 in weight. We added acetylene black as a conductive additive and PTFE as a binder. The cathode was made by pressing the paste on a current collector. We used 35% H2SO4 as electrolyte and lead plate as anode. First experiment is the long term deep-discharge durability test. The cycle was consisted of 4 times of discharge down to 0V and full charge, and then 48 h rest period. Charge/discharge rate was 180 mAg-1 for charge and 9 mAg-1 for discharge. The stabilization cycle prior to deep-discharge was consisted of 20 cycles of discharge at 9 mAg-1 for 30 min and charge at 180 mAg-1 for 20 min. We determined charge and discharge rates by weight of cathode active material. The second experiment is to evaluate durability against over-discharge followed by various rest period. After the stabilization cycle, we discharged the cell down to 0V and kept it in open-circuit for various period, and then rechargeablity was examined by charging the cell. Results and discussion Fig.1 shows the result of the first experiment. The LAB using 5 wt% polypropylene-dispersed graphite sheet current collector continued the cycle of 4 times charge/deep-discharge and 48 h rest for more than 5 months. The cause of the breakage of the cell after 5 months was due to fall of active material off the current collector. It is thought that this cell could charge/discharge for longer term by improving the filling method of active material. This result shows that this type of battery has high durability to deep-discharge for long term. Fig.2 shows the result of the second experiment. The rest period was 2 d or 1 week. It was found that the cell was rechargeable for either rest period. It was confirmed that The LAB using 5 wt% polypropylene-dispersed graphite sheet current collector has high durability to both over-discharged and long term rest. References [1] T. Iwai, D. Kitajima, S. Takai, T. Yabutsuka and T. Yao, J. Electrochem. Soc. Vol 163, Issue 14, A3087-A3090 (2016) [2] T.Iwai, M.Murakami, S.Takai, T.Yabutsuka and T.Yao, Journal of Alloys and Compounds, Vol 780, 85-89 (2019) [3] T.Yao, H.Okano, T.Iwai, S.Takai, T.Yabutsuka, T.Hosokawa, N.Misaki, K.Kurihara “Positive Electrode for Lead Storage Battery and Lead Storage Battery Using Same” PCT/JP2018/005947 [4] Y.Nakamura, T.Ohkubo, H.Okano, T.Inoue, T.Hosokawa, A.Takeda, T.Iwai, T.Yabutsuka, S.takai and T.Yao, 235th Electrochem. Soc. Z01-2143 (2019) Figure 1

Lead acid battery has been one of the most important battery for industry use. However, conventional lead acid battery cannot be recharged after over discharge and the performance is greatly declined. It has been revealed that the cause of not being able to be recharged is the formation of α‐PbO2 on the surface of β‐PbO2 cathode active material due to local cell reaction between lead current collector and β‐PbO2. Formation of α‐PbO2 is prevented by using gold as the current collector. In this study, we developed the lead acid battery with high resistance to over discharge using graphite materials as current collector. The formation of α‐PbO2 was prevented by using expanded natural graphite sheet as cathode current collector. The lead acid battery with current collector of expanded natural graphite sheet containing 5% polypropylene (PP) can repeat deep charge and discharge between 0 and 2 V for more than about 6 months and showed flat potential area between 1.9 and 1.3 V for every cycle. Furthermore, this battery can be charged again after over discharge for more than 4 month at the open circuit. We have succeeded to develop high performance lead acid battery.

Introduction Conventionally, Lead Acid Battery (LAB) cannot be recharged after over-discharge and its performance is greatly degraded. We have revealed that the above deterioration is caused by the formation of α-PbO2 on the surface of cathode active material β-PbO2 due to the reduction by local cell reaction between β-PbO2 and lead current collector. We revealed that the formation of α-PbO2 can be prevented by using gold instead of lead as cathode current collector and that this operation made the LAB rechargeable even after over-discharge [1,2]. We have also revealed that the LAB using graphite sheet as a current collector can charge-discharge even the circuit is opened for 48 h after over-discharge to 0V [3]. Especially in the improvement of tensile strength and discharge potential, it is concluded that 5wt% polypropylene addition to raw graphite sheet is most suitable for use as a cathode current collector in our previous study [4]. In this study, for practical use of this type of LAB, we investigated its characteristics, in particular the relationship between discharge energy and charge voltage. Experiment We used two-electrode glass cell for charge-discharge experiments. The cathode slurry was prepared by mixing β-PbO2 powder as active material, acetylene black as conductive additive and polyvinylidene fluoride as binder at the ratio of 8:1:1 in weight with solvent of N-methyl-pyrrolidone. We used graphite composite sheet with 5wt% polypropylene mixed for cathode current collector. We constructed the cathode by applying the cathode slurry to the current collector. We used 35% H2SO4 as electrolyte and lead plate as anode. As the stabilization cycle, we repeated discharge at 45μA cm2 -1 for 30 min and charge at 0.9 mA cm2 -1 for 20 min for 20 times, then we conducted charge discharge experiment. We determined charge-discharge rate using the coating area of cathode active material. Results and discussion Figure 1 shows the typical charge/discharge curve between 0 V and 2 V of the LAB using graphite sheet with 5wt% polypropylene as cathode current collector at about 1C discharge. It was confirmed that this LAB could be discharged to 0V and that showed flat discharge potential around between 2V and 0.7V. We charged this LAB to various potential and discharged to 0V. We calculated the discharge energy by the integral of the obtained discharge curve from each charge potential to 0.7V. Figure 2 shows discharge energy ratio at 2.0V, 1.8V, 1.6V and 1.4V charge voltage to discharge energy at 2.0V charge voltage. Discharge energy increased with charge voltage. It was found that this LAB using graphite composite sheet with 5wt% polypropylene mixed for cathode current collector could recover more than 50% of discharge energy obtained at 2.0V charge by charging to 1.8V. References [1] T. Iwai, D. Kitajima, S. Takai, T. Yabutsuka and T. Yao, J. Electrochem. Soc. Vol 163, Issue 14, A3087-A3090 (2016) [2] T. Iwai, M. Murakami, S. Takai, T. Yabutsuka and T. Yao, Journal of Alloys and Compounds, Vol 780, 85-89 (2019) [3] T. Yao, H. Okano, T. Iwai, S. Takai, T. Yabutsuka, T. Hosokawa, N. Misaki, K. Kurihara “Positive Electrode for Lead Storage Battery and Lead Storage Battery Using Same” PCT/JP2018/005947 [4] Y. Hano, H. Okano, T. Inoue, T. Hosokawa, A. Takeda, T. Iwai, T. Yabutsuka, S. Takai and T. Yao, 238th Electrothem. Soc. Z01-3448 (2020) Figure 1