Effect of binary conductive additive mixtures on electrochemical performance of polyoxomolybdate as cathode material of lithium ion battery

Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the cathode material polyoxomolybadate Na_3[AlMo_6O_(24)H_6](NAM). Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy show that the surfaces of NAM particles are covered homogeneously with the binary conductive additive mixtures except the combination of ECP and CNT. The optimum combination is the mixture of ECP and VGCF, which shows higher discharge capacity than the combinations of ECP and CNT or Gr. Initial discharge capacities of 364, 339, and 291 m A·h/g are obtained by the combination of ECP and VGCF in the mass ratios of 2:1, 1:1, and 1:2, respectively. The results of electrochemical impedance spectra and 4-pin probe measurements demonstrate that the combination of ECP and VGCF exhibits the highest electrical conductivity for the electrode.

High-efficiency,self-grinding exfoliation of small graphene nanosheets from microcrystalline graphite driven by microbead milling as conductive additives

Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging.This work proposes self-grinding exfoliation using the mutual shear friction of graphite particles to fabricate graphene from microcrystalline graphite.The concept is implemented using microbeads as the grinding medium to drive the shear friction between graphite nanocrystals in a high-concentration paste.The proposed approach substantially improves graphene yield from 6.3% to 100% and simultaneously generates a record productivity of 7.5 g h^(-1)L^(-1),achieving total graphite-to-graphene conversion on the kilogram scale.The as-prepared graphene nanosheets have an average lateral size of 298 nm and the same C/O atomic ratio as the pristine graphite.In addition,the well-exfoliated,small nanosheets display good electrical conductivity and exhibit significant potential as conductive additives that improve the specific capacity and cyclic stability of Li-ion batteries better than commercial carbon-based conductive particles.

Weak Intermolecular Interactions for Strengthening Organic Batteries

Organic batteries have attracted a lot of attention due to the advantages of flexibility,light weight,vast resources,low cost,recyclability,and ease to be functionalized through molecular design.The biggest difference between organic materials and inorganic materials is the relatively weak intermolecular interactions in organic materials but strong covalent or ionic bonds in inorganic materials,which is the inherent reason of their different physiochemical and electrochemical characteristics.Therefore,the relatively weak intermolecular interactions can indisputably affect the electrochemical performance of organic batteries significantly.Herein,the intermolecular interactions that are closely related to organic redox-active materials and unique in organic batteries are summarized into three parts:1)between neighbor active molecules,2)between active molecules and the conduction additives,and 3)between active molecules and the binders.We hope this short review can give a distinct viewpoint for better understanding the internal reasons of high-performance batteries and stimulate the deep studies of relatively weak intermolecular interactions for strengthening the performance of organic batteries.

Applications of carbon nanotubes in high performance lithium ion batteries

The development of lit;triton ion batteries （LIBs） relies on the improvement in the performance of electrode materials with higher capacity, higher rate capability, and longer cycle lift;. In this review article, the recent advances in carbon nanotube （CNT） anodes, CNT-based composite electrodes, and CNT current collectors for high performance LIBs are concerned. CNT has received considerable attentions as a candidate material for the LIB applications. In addition to a possible choice for anode, CNT has been recognized as a solution in improving the performance of the state-of-the-art electrode materials. The CNT-based composite electrodes can be fabricated by mechanical or chem- ical approaches. Owing to the large aspect ratio and the high electrical conductivity, CNTs at very low loading can lead to an efficient conductive network. The excellent mechanical strength suggests the great potential in forming a structure scaffold to accommodate nano-sized electrode materials. Accordingly, the incorporation of CNTs will enhance the conductivity of the composite electrodes, mitigatc the agglomeration problem, decrease the dependence on inactive binders, and improve the clcctrochenfical properties of both anode and cathode materials remarkably. Freestanding CNT network can be used as lightweight current collectors to increase the overall energy density of LIBs. Finally, research perspectives for exploiting CNTs in high-performance LIBs are discussed.