Septian Aditya - Academia.edu (original) (raw)
Papers by Septian Aditya
Advanced Materials Interfaces, 2019
with natural abundance and low discharge potential, it has been considered as one of the most pro... more with natural abundance and low discharge potential, it has been considered as one of the most promising candidate as next generation anode materials for LIBs. [5] However, Si anode have fast failure problems of structure degradation, unsatisfactory coulombic efficiency (CE), and rapid capacity fading due to the large volume variation (≈300%) and unstable solid-electrolyte interphase (SEI) during alloying/dealloying process. With the fundamental understanding of failure mechanisms of Si anode, different approaches have been investigated by researchers. 1) Building various Si nanostructures to solve the volume expansion problem. [6-14] 2) Developing different coating strategy to enhance its structural stability and reducing SEI formation. [15-18] 3) Using additives in the electrolyte to stabilize the SEI. [19,20] However, the cycling performance of Si anode still needs to be improved. The capacity decay of Si anode is generally ascribed to a combination of volume variation and SEI formation, and there are also evidences indicating that lithium trapping is also one of the important factors to affect the electrochemical performance of Si electrodes. [21-23] The lithium trapping causes capacity decay due to incomplete delithiation of Si during high rate cycling, leading to capacity decay and unsatisfactory columbic efficiency. Despite all these above, lithium trapping has received relatively little attention so far, and it requires further investigation. Here, we have designed a new Si@LiAlO 2 structure by synthesizing LiAlO 2 thin coating on Si nanoparticles. The LiAlO 2 coating serves as an artificial SEI film with better lithium-ion diffusivity than naturally formed SEI layer, which enhances the rate performance and reduces the lithium trapping. By carrying out in situ Raman measurements on the LiAlO 2 coated Si anode, we have investigated the alloying process of Si during lithiation and confirmed LiAlO 2 can enhance the alloying process during lithiation. Owing to the LiAlO 2 coating, the Si anode demonstrates a superior electrochemical performance, which presents a specific capacity of 2013 mAh g −1 at a current density of 1000 mAh g −1 and 1106 mAh g −1 at a current density of 4000 mA g −1 with a capacity retention of 90.9% after 500 cycles.
Journal of Hazardous Materials, 2019
Suppose the president sought to serve as prosecutor-in-chief, telling prosecutors when to initiat... more Suppose the president sought to serve as prosecutor-in-chief, telling prosecutors when to initiate or dismiss criminal charges in individual cases and making other discretionary decisions that are normally reserved to trained professionals familiar with the facts, law, and traditions of the U.S. Department of Justice. To what extent may prosecutors follow the president's direction? In recent presidential administrations, the president has respected prosecutorial independence; while making policy decisions, the president deferred to the Attorney General and subordinate federal prosecutors to conduct individual criminal cases. In a recent article, we argued that this is as it should be because the president has no constitutional or statutory authority to control federal criminal prosecutions. But suppose one comes to the contrary conclusion-that the president, as chief executive, has authority to decide how individual criminal prosecutions should be conducted. In this Article, we explore the consequences for prosecutors who receive the president's orders. We argue here that federal prosecutors cannot invariably and unquestioningly follow the president's direction because doing so would violate ethical rules and professional norms. Further, because prosecutors' professional obligations are created by courts and endorsed by federal statute, presidential control over prosecutorial decision-making would lead to serious separation-of-powers concerns. Particularly, the integrity of the judicial system depends on the ethical rules at issue. By exploring these separation-of-powers concerns, this Article contributes to a growing debate about the power of the executive over prosecution and further supports the independence of the DOJ and federal prosecutors.
Journal of Power Sources, 2019
The backside-lithium-plating design can ensure safe battery operation. • Control of Li deposition... more The backside-lithium-plating design can ensure safe battery operation. • Control of Li deposition in both growth direction and morphology is achieved. • The optimized Li anode exhibits a long-term stable cycling. • The featured anode shows potential for practical application in full battery.
ACS Sustainable Chemistry & Engineering, 2018
Three-dimensional (3D) porous N-doped carbon nanoflakes structures decorated with in-situ formed ... more Three-dimensional (3D) porous N-doped carbon nanoflakes structures decorated with in-situ formed Ag nanoparticles (Ag-NCNS) have been first synthesized by a feasible salt-assisted polymer blowing-up method. The 3D porous carbon materials can be an effective lithium host for the application of lithium metal batteries (LMBs) to address the challenging issues of the growth of lithium dendrites and uncontrollable formation of solid electrolyte interphase (SEI). The 3D hosts can effectively restrain the growth of Li dendrites by trapping metallic Li in the matrix as well as decreasing local current. Ag nanoparticles perform as heterogeneous nucleation sites due to the low nucleation overpotential, and therefore, spatial control of Li metal is realized. The as-fabricated Ag-NCNS electrode presents dendrite-free plating morphology and long-term cycling stability with the Coulombic efficiency maintaining at more than 98% for 200 cycles at 0.5 mA cm-2 with a cycling capacity of 1.0 mA h cm-2. In symmetric cells, the Ag-NCNS/Li electrode exhibits much lower voltage hysteresis and stable cycling performance for above 2000 h.
ACS applied materials & interfaces, Jan 14, 2018
The electrode-electrolyte interface stability is a critical factor influencing cycle performance ... more The electrode-electrolyte interface stability is a critical factor influencing cycle performance of All-solid-state lithium batteries (ASSLBs). Here, we propose a LiF&Li3N-enriched artificial solid state electrolyte interphase (SEI) protective layer on metallic Lithium (Li). The SEI layer can stabilize metallic Li anode and improve the interface compatibility at the Li anode side in ASSLBs. We also developed a Li1.5Al0.5Ge1.5(PO4)3-poly(ethylene oxide) (LAGP-PEO) concrete structured composite solid electrolyte. The symmetric Li/LAGP-PEO/Li cells with SEI-protected Li anodes have been stably cycled with small polarization at a current density of 0.05 mA cm-2 at 50 oC for nearly 400 h. ASSLB based on SEI-protected Li anode, LAGP-PEO electrolyte, and LiFePO4 (LFP) cathode exhibits excellent cyclic stability with an initial discharge capacity of 147.2 mA h g-1 and a retention of 96 % after 200 cycles.
Advanced Materials Interfaces, 2019
with natural abundance and low discharge potential, it has been considered as one of the most pro... more with natural abundance and low discharge potential, it has been considered as one of the most promising candidate as next generation anode materials for LIBs. [5] However, Si anode have fast failure problems of structure degradation, unsatisfactory coulombic efficiency (CE), and rapid capacity fading due to the large volume variation (≈300%) and unstable solid-electrolyte interphase (SEI) during alloying/dealloying process. With the fundamental understanding of failure mechanisms of Si anode, different approaches have been investigated by researchers. 1) Building various Si nanostructures to solve the volume expansion problem. [6-14] 2) Developing different coating strategy to enhance its structural stability and reducing SEI formation. [15-18] 3) Using additives in the electrolyte to stabilize the SEI. [19,20] However, the cycling performance of Si anode still needs to be improved. The capacity decay of Si anode is generally ascribed to a combination of volume variation and SEI formation, and there are also evidences indicating that lithium trapping is also one of the important factors to affect the electrochemical performance of Si electrodes. [21-23] The lithium trapping causes capacity decay due to incomplete delithiation of Si during high rate cycling, leading to capacity decay and unsatisfactory columbic efficiency. Despite all these above, lithium trapping has received relatively little attention so far, and it requires further investigation. Here, we have designed a new Si@LiAlO 2 structure by synthesizing LiAlO 2 thin coating on Si nanoparticles. The LiAlO 2 coating serves as an artificial SEI film with better lithium-ion diffusivity than naturally formed SEI layer, which enhances the rate performance and reduces the lithium trapping. By carrying out in situ Raman measurements on the LiAlO 2 coated Si anode, we have investigated the alloying process of Si during lithiation and confirmed LiAlO 2 can enhance the alloying process during lithiation. Owing to the LiAlO 2 coating, the Si anode demonstrates a superior electrochemical performance, which presents a specific capacity of 2013 mAh g −1 at a current density of 1000 mAh g −1 and 1106 mAh g −1 at a current density of 4000 mA g −1 with a capacity retention of 90.9% after 500 cycles.
Journal of Hazardous Materials, 2019
Suppose the president sought to serve as prosecutor-in-chief, telling prosecutors when to initiat... more Suppose the president sought to serve as prosecutor-in-chief, telling prosecutors when to initiate or dismiss criminal charges in individual cases and making other discretionary decisions that are normally reserved to trained professionals familiar with the facts, law, and traditions of the U.S. Department of Justice. To what extent may prosecutors follow the president's direction? In recent presidential administrations, the president has respected prosecutorial independence; while making policy decisions, the president deferred to the Attorney General and subordinate federal prosecutors to conduct individual criminal cases. In a recent article, we argued that this is as it should be because the president has no constitutional or statutory authority to control federal criminal prosecutions. But suppose one comes to the contrary conclusion-that the president, as chief executive, has authority to decide how individual criminal prosecutions should be conducted. In this Article, we explore the consequences for prosecutors who receive the president's orders. We argue here that federal prosecutors cannot invariably and unquestioningly follow the president's direction because doing so would violate ethical rules and professional norms. Further, because prosecutors' professional obligations are created by courts and endorsed by federal statute, presidential control over prosecutorial decision-making would lead to serious separation-of-powers concerns. Particularly, the integrity of the judicial system depends on the ethical rules at issue. By exploring these separation-of-powers concerns, this Article contributes to a growing debate about the power of the executive over prosecution and further supports the independence of the DOJ and federal prosecutors.
Journal of Power Sources, 2019
The backside-lithium-plating design can ensure safe battery operation. • Control of Li deposition... more The backside-lithium-plating design can ensure safe battery operation. • Control of Li deposition in both growth direction and morphology is achieved. • The optimized Li anode exhibits a long-term stable cycling. • The featured anode shows potential for practical application in full battery.
ACS Sustainable Chemistry & Engineering, 2018
Three-dimensional (3D) porous N-doped carbon nanoflakes structures decorated with in-situ formed ... more Three-dimensional (3D) porous N-doped carbon nanoflakes structures decorated with in-situ formed Ag nanoparticles (Ag-NCNS) have been first synthesized by a feasible salt-assisted polymer blowing-up method. The 3D porous carbon materials can be an effective lithium host for the application of lithium metal batteries (LMBs) to address the challenging issues of the growth of lithium dendrites and uncontrollable formation of solid electrolyte interphase (SEI). The 3D hosts can effectively restrain the growth of Li dendrites by trapping metallic Li in the matrix as well as decreasing local current. Ag nanoparticles perform as heterogeneous nucleation sites due to the low nucleation overpotential, and therefore, spatial control of Li metal is realized. The as-fabricated Ag-NCNS electrode presents dendrite-free plating morphology and long-term cycling stability with the Coulombic efficiency maintaining at more than 98% for 200 cycles at 0.5 mA cm-2 with a cycling capacity of 1.0 mA h cm-2. In symmetric cells, the Ag-NCNS/Li electrode exhibits much lower voltage hysteresis and stable cycling performance for above 2000 h.
ACS applied materials & interfaces, Jan 14, 2018
The electrode-electrolyte interface stability is a critical factor influencing cycle performance ... more The electrode-electrolyte interface stability is a critical factor influencing cycle performance of All-solid-state lithium batteries (ASSLBs). Here, we propose a LiF&Li3N-enriched artificial solid state electrolyte interphase (SEI) protective layer on metallic Lithium (Li). The SEI layer can stabilize metallic Li anode and improve the interface compatibility at the Li anode side in ASSLBs. We also developed a Li1.5Al0.5Ge1.5(PO4)3-poly(ethylene oxide) (LAGP-PEO) concrete structured composite solid electrolyte. The symmetric Li/LAGP-PEO/Li cells with SEI-protected Li anodes have been stably cycled with small polarization at a current density of 0.05 mA cm-2 at 50 oC for nearly 400 h. ASSLB based on SEI-protected Li anode, LAGP-PEO electrolyte, and LiFePO4 (LFP) cathode exhibits excellent cyclic stability with an initial discharge capacity of 147.2 mA h g-1 and a retention of 96 % after 200 cycles.