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Polyaniline (PANI) has long been explored as a promising organic cathode for Li-ion batteries. However, its poor electrochemical utilization and cycling instability cast doubt on its potential for practical applications. In this work, we revisit the electrochemical performance of PANI in nonaqueous electrolytes, and reveal an unprecedented reversible capacity of 197.2 mAh g−1 (244.8 F g−1) when cycled in a wide potential range of 1.5 to 4.4 V vs. Li+/Li. This ultra-high capacity derives from 70% -NH- transformed to =NH+- during deep charging/discharging process. This material also demonstrates a high average coulombic efficiency of 98%, an excellent rate performance with 73.5 mAh g−1 at 1800 mA g−1, and retains 76% of initial value after 100 cycles, which are among the best reported values for PANI electrodes in battery applications. [ABSTRACT FROM AUTHOR]

Stable solid electrolyte interphase (SEI) with high Li+‐ion conductivity is desperately desired for lithium (Li) metal anodes. However, it remains challenging to build a robust SEI rationally for the Li‐metal anodes in carbonate electrolytes. Herein, a heterogeneous nitride‐rich SEI that consists of organic nitrides on the surface and inorganic nitrides inside by stepwise‐reduction electrolyte design is constructed. The heterogeneous structure endows SEI with the capability to capture and distribute Li+ on the surface and facilitate internal Li+ transportation, leading to the redistributed Li+ flux and uniform Li electrodeposition. With the newly‐formulated carbonate electrolyte, Li||Cu cells deliver a high Coulombic efficiency of 98.0% after 300 cycles at 0.5 mA cm‐2 and 0.5 mAh cm‐2. Meanwhile, superb cycling stability is also determined with full Li‐metal cells using LiNi1/3Mn1/3Co1/3O2 and high‐loading LiFePO4 (12.0 mg cm−2) cathodes. This study provides a promising strategy to regulate the SEI components and stabilize the Li anodes by rational electrolyte design. [ABSTRACT FROM AUTHOR]

The spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) material is considered as a promising cathode in high-voltage lithium-ion batteries due to its advantageous voltage and capacity. Previous results indicate that the electrodes constructed by LNMO with the same compositions while differing in the crystallite geometries always exhibit various electrochemical performances. Here, to probe the relationships between the crystalline geometry of the obtained cathodes and their electrochemical properties, we synthesized different facet-exposed LNMOs with the same compositions using a template method. We demonstrate that the crystallite geometries of the hydroxide precursors can be tuned easily via varying the synthesize parameters, while the tuned precursors can be employed as the templates during the final product preparation. LNMOs enclosed by single {111} facets (LNMO-OH) and both {110} and {100} facets (LNMO-HP) are obtained and employed to elucidate the particle geometry-dependent electrochemical properties. Despite better rate capabilities exhibited for LNMO-HP because of the higher lithium diffusion coefficients along these crystal orientations, inferior cycling performance is released compared with its LNMO-OH counterpart. These insights can provide informative guidance in particle geometry-dependent material construction, thus helpful in realizing high-performance LNMO cathode. • Different facet-exposed LNMOs with the same compositions were synthesized. • The crystallite geometries of the hydroxide precursors can be tuned easily via varying the synthesize parameters. • Facet-exposed LNMOs exhibit various electrochemical properties. • Working mechanism of different LNMOs was investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel PDDA/GO dual-layer coating strategy to effectively improve the performance of NCM811 is proposed in this paper. • NCM811 particles can be well-encapsulated in the resultant dual-layer by a simple electrostatic adsorption method. • The PDDA/GO coating depresses the LiF component, enables a homogeneous organic-enriched CEI film with fast Li diffusion and effective corrosion protection on cathodes. • NCM811-PDDA/GO cathodes exhibit a 77% capacity retention after 500 cycles at the current density of 50 mA g−1, against 28% for pristine NCM811. Cathode-electrolyte interphases (CEIs) are determinative to the electrochemical performance of lithium-ion batteries, especially those with Ni-rich cathodes. Herein, we employed the simple electrostatic adsorption (SEA) method to generate a homogenous polydimethyldiallyl ammonium chloride/ graphene oxide (PDDA/GO) dual-layer coating on the surface of a model single-crystalline Ni-rich cathode, LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), and thus modified the CEIs in both compositions and microstructures. The PDDA/GO coating depresses the LiF component, enables a homogeneous organic-enriched CEI film with fast Li diffusion and effective corrosion protection on cathodes. Together with the mechanical confinement on cathodes, these characters of modified CEIs benefit the electrochemical stability effectively. For instance, NCM811-PDDA/GO cathodes exhibit a 77% capacity retention after 500 cycles at the current density of 50 mA g−1, against 28% for pristine NCM811. This study provides new insights in correlating the coating and CEIs, which effectively guide the development of Ni-rich cathodes for high performance. Such a simple strategy to form a homogeneous coating can also be extended into other electrode materials easily. [ABSTRACT FROM AUTHOR]