Silver in the linings: The bacterium Shewanella oneidensis is well known to use extracellular electron sinks, metal oxides and ions in nature or electrodes when cultured in a fuel cell, to power the catabolism of organic material. However, the power density of microbial fuel cells has been limited by various factors that are mostly related to connecting the microbes to the anode. Cao et al . found that a reduced graphene oxide–silver nanoparticle anode circumvents some of these issues, providing a substantial increase in current and power density (see the Perspective by Gaffney and Minteer). Electron microscopy revealed silver nanoparticles embedded or attached to the outer cell membrane, possibly facilitating electron transfer from internal electron carriers to the anode. —MAF
Nickel-rich layered oxide cathodes promise ultrahigh energy density but is plagued by the mechanical failure of the secondary particle upon (de)lithiation. Existing approaches for alleviating the structural degradation could retard pulverization, yet fail to tune the stress distribution and root out the formation of cracks. Herein, we report a unique strategy to uniformize the stress distribution in secondary particle via Kirkendall effect to stabilize the core region during electrochemical cycling. Exotic metal/metalloid oxides (such as Al2O3 or SiO2) is introduced as the heterogeneous nucleation seeds for the preferential growth of the precursor. The calcination treatment afterwards generates a dopant-rich interior structure with central Kirkendall void, due to the different diffusivity between the exotic element and nickel atom. The resulting cathode material exhibits superior structural and electrochemical reversibility, thus contributing to a high specific energy density (based on cathode) of 660 Wh kg−1 after 500 cycles with a retention rate of 86%. This study suggests that uniformizing stress distribution represents a promising pathway to tackle the structural instability facing nickel-rich layered oxide cathodes.
Herein, we demonstrate that the battery intrinsic electric field drives the specific adsorption of a weakly solvated co-solvent, DTS, to replace conventional DME in the IHP, enabling the desirable CEI chemistry on the 4.6 V LiCoO 2 cathode.
Lithium–sulfur (Li–S) battery is attracting increasing interest for its potential in low‐cost high‐density energy storage. However, it has been a persistent challenge to simultaneously realize high energy density and long cycle life. Herein, we report a synergistic strategy to exploit a unique nitrogen‐doped three‐dimensional graphene aerogel as both the lithium anode host to ensure homogeneous lithium plating/stripping and mitigate lithium dendrite formation and the sulfur cathode host to facilitate efficient sulfur redox chemistry and combat undesirable polysulfide shuttling effect, realizing Li–S battery simultaneously with ultrahigh energy density and long cycle life. The as‐demonstrated polysulfide‐based device delivers a high areal capacity of 7.5 mAh/cm2 (corresponds to 787 Wh/L) and an ultralow capacity fading of 0.025% per cycle over 1000 cycles at a high current density of 8.6 mA/cm2. Our findings suggest a novel strategy to scale up the superior electrochemical property of every microscopic unit to a macroscopic‐level performance that enables simultaneously high areal energy density and long cycling stability that are critical for practical Li–S batteries.