Andrew P. Baker

Na-X zeolite templated and sulfur-impregnated porous carbon as the cathode for a high-performance Li–S battery

Significant efforts have recently been devoted to developing commercially viable high-capacity and low-cost lithium sulfur (Li–S) batteries. In this paper, we report Na-X zeolite templated porous carbon (ZPC) filled with sulfur as a cathode material for Li–S batteries. To immobilize liquid Li sulfide, the surface of NCP was modified by amphiphilic N-polyvinylpyrrolidone (PVP), making ZPC amphiphilic (denoted as A-ZPC). ZPC, A-ZPC and their corresponding composites with sulfur (ZPC–S and A-ZPC–S) were analyzed by various physical characterizations, charge–discharge profiling and electrochemical impedance spectroscopy (EIS). The results showed excellent performance of the A-ZPC–S composite cathode with 46 wt% sulfur loading, a specific capacity can be retained at 691 mA h g−1 even after 300 cycles under a rate of 1C, fading only 0.142% per cycle.

Fabrication of La2NiO4 nanoparticles as an efficient bifunctional cathode catalyst for rechargeable lithium–oxygen batteries

Efficient catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are crucial enabling materials for rechargeable Li–O2 batteries. In the present work, La2NiO4 (LNO) synthesized by a hydrothermal process and modified Pechini method were studied as catalysts for rechargeable Li–O2 batteries. The catalyst prepared by the hydrothermal method shows a smaller particle size and a macroporous structure with 10× higher surface area than that synthesized by the Pechini counterpart, leading to a better electrocatalytic activity. The improved OER catalytic activity of the hydrothermal-LNO nanoparticles was confirmed by a 150 mV lower recharge potential than the Pechini-LNO particles and catalyst-free pure Super P (SP) electrode. In addition, the hydrothermal-LNO catalyzed battery cell delivered a first discharge capacity of 14 310.9 mA h g−1 at 0.16 mA cm−2, compared to 8132.4 mA h g−1 of the Pechini-LNO and 7478.8 mA h g−1 of the pure SP electrode, demonstrating higher catalytic ORR activity of the hydrothermal-LNO particles. Overall, the LNO nanoparticles are a promising cathode catalyst for non-aqueous electrolyte based Li–O2 batteries.

A novel sulfur-impregnated porous carbon matrix as a cathode material for a lithium–sulfur battery

A novel sulfur-impregnated porous carbon matrix (PCM-Z-S) has been prepared as a cathode material for a lithium–sulfur battery. The porous carbon matrix (PCM-Z), which was obtained using de-waxed cotton and ZnCl2 as an activator, has a surface area of 1056 m2 g−1 and a pore volume of 1.75 cm3 g−1. The PCM-Z was mixed with sublimed sulfur and then heated in nitrogen gas to form a carbon–sulfur 58 wt% composite (PCM-Z-S) which has excellent electrochemical proprieties. The PCM-Z-S delivers a capacity of 850 mA h g−1 at 1C and retains 630 mA h g−1 after nearly 200 cycles which are values much higher than that of a carbon matrix prepared without ZnCl2. These results show the sulfur-impregnated porous carbon matrix (PCM-Z-S) has great potential as a cathode material in a lithium–sulfur battery.

Acoustic aligning of micro-particles by phononic crystal slab

Among various manipulation methods, acoustic manipulation has some advantages including penetrability, non-contact and versatility, without any biochemical decorations to particles. Recently, we have theoretically demonstrated that phononic crystal slab (PCS) can generate periodically gradient field near the surface, which can be used for trapping particles. In this letter, we experimentally realize aligning polystyrene micro-particles by PCS. The PCS we fabricated consists of a stainless steel slab patterned with periodical arrays of rectangular gratings on the downside, and the upside of the plane surface is used for particle manipulation. Since the manipulation system is fabricated on a chip, which can be easily integrated with MEMS technology and combined with other micro-processing technology, we believe this technology can be developed to meet the needs of non-contact and precise manipulation of cells and biological particles.