Bio-based poly(benzimidazole-co-amide)-derived N, O co-doped carbons as fast-charging anodes for lithium-ion batteries.

Lithium-ion batteries (LIBs) that can be charged faster while delivering high capacity are currently in significant demand, especially for electric vehicle applications. In this context, this study introduces a less-explored subject: nitrogen and oxygen dual-doped carbons derived from bio-based copolymers, specifically poly(benzimidazole-co-amide). The synthesis involved varying proportions of benzimidazole to amide, namely, 8.5 : 1.5, 7 : 3, and 5 : 5. The copolymers were pyrolyzed under a nitrogen atmosphere to obtain co-doped carbons, wherein the copolymers acted as single sources of carbon, nitrogen, and oxygen, with the nitrogen content ranging between 12.1 and 8.0 at% and oxygen doping between 11.8 and 25.0 at%, and were named as pyrolyzed polybenzimidazole-co-amide 8.5-1.5, 7-3, and 5-5. Coin cells were fabricated and rate studies were conducted for all three samples, wherein PYPBIPA8.5-1.5 outperformed all others, especially at higher current densities. Intrigued by these interesting results, when long-cycling studies were performed at a high current density of 4.0 A g-1, pyrolysed polybenzimidazole-co-amide 8.5-1.5 showed a delithiation capacity of 135 mA h g-1 compared to pyrolysed polybenzimidazole-co-amide 7-3 and 5-5 with a delithiation capacity of 100 mA h g-1 and 60 mA h g-1, respectively, with a capacity retention of 90% even after 3000 cycles. Furthermore, a full cell (2025-coin cell) was fabricated using the PYPBIPA8.5-1.5 anode and LiNi0.80 Co0.15Al0.05O2 (LiNCAO) cathode.

Microbial pyrazine diamine is a novel electrolyte additive that shields high-voltage LiNi1/3Co1/3Mn1/3O2 cathodes.

The uncontrolled oxidative decomposition of electrolyte while operating at high potential (> 4.2 V vs Li/Li+) severely affects the performance of high-energy density transition metal oxide-based materials as cathodes in Li-ion batteries. To restrict this degradative response of electrolyte species, the need for functional molecules as electrolyte additives that can restrict the electrolytic decomposition is imminent. In this regard, bio-derived molecules are cost-effective, environment friendly, and non-toxic alternatives to their synthetic counter parts. Here, we report the application of microbially synthesized 2,5-dimethyl-3,6-bis(4-aminobenzyl)pyrazine (DMBAP) as an electrolyte additive that stabilizes high-voltage (4.5 V vs Li/Li+) LiNi1/3Mn1/3Co1/3O2 cathodes. The high-lying highest occupied molecular orbital of bio-additive (DMBAP) inspires its sacrificial in situ oxidative decomposition to form an organic passivation layer on the cathode surface. This restricts the excessive electrolyte decomposition to form a tailored cathode electrolyte interface to administer cyclic stability and enhance the capacity retention of the cathode.

Extremely fast charging lithium-ion battery using bio-based polymer-derived heavily nitrogen doped carbon.

Extremely high nitrogen doped carbon was designed by facile pyrolysis of bio-based poly(2,5-benzimidazole) as a single source of nitrogen and carbon. For the first time ever, a carbon-based anode with ∼17 wt% of nitrogen doping with extremely fast charging (XFC) capability at 18.6 A g-1 and ultralong cyclability (3000 cycles) with 90% capacity retention was investigated. Full cell studies also indicated the commercial competence of the novel material.

Few-Layered MoS2/Acetylene Black Composite as an Efficient Anode Material for Lithium-Ion Batteries.

Novel MoS2/acetylene black (AB) composite was developed using a single-step hydrothermal method. A systematic characterization revealed a few-layered, ultrathin MoS2 grown on the surface of AB. The inclusion of AB was found to increase the capacity of the composite and achieve discharging capacity of 1813 mAhg-1.

Sacrificial Reducing Agent Free Photo-Generation of Platinum Nano Particle over Carbon/TiO2 for Highly Efficient Oxygen Reduction Reaction.

Electrocatalytic materials for oxygen reduction reaction, currently dominated by platinum/carbon catalyst is marred by drawbacks such as use of copious amount of Pt and use of "non-green" sacrificial reducing agent (SRA) during its synthesis. A single stroke remedy for these two problems has been achieved through an in-situ aqueous photoreduction void of even trace amounts of SRA with an enhanced activity. Reduction of PtCl62- salt to Pt nano particles on carbon substrate was achieved solely using solar spectrum as the source of energy and TiO2 as photocatalyst. Here, we demonstrate that this new procedure of photoreduction, decorates Pt over different types of conducting allotropes with the distribution and the particle size primarily depending on the conductivity of the allotrope. The Pt/C/TiO2 composite unveiled an ORR activity on par to the most efficient Pt based electrocatalyst prepared through the conventional sacrificial reducing agent aided preparation methods.

Platinum decorated functionalized defective acetylene black; a promising cathode material for the oxygen reduction reaction.

A novel single-pot method to exfoliate and functionalize acetylene black is proposed. The deliberate functionalization was found to enhance the intrinsic oxygen reduction efficiency along with the nucleation and growth of platinum nano-particles on the surface. The resulting material showed enormously high oxygen reduction reactivity compared to its commercial counterparts.