Lithium metal anode (LMA) possesses the highest energy density among all anode candidates, while dendrite growth is a huge barrier in the direct application of LMA in batteries.
Lithium metal anode (LMA) processes the largest energy density among all anode candidates while dendrite growth is a huge barrier in the direct application of LMA in batteries. Herein, ultrathin...
Electrochemical and chemical interfacial reaction mechanisms between LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NMC532) and poly(propylene carbonate) solid polymer electrolyte (PPC-SPE) are studied. Ni 3+ and Co 4+ species which are electrochemically oxidized from Ni 2+ and Co 3+ during the charging process will induce the decomposition of PPC. Fourier transform infrared spectroscopy (FT-IR) and 1 H nuclear magnetic resonance (NMR) analysis confirm that the decomposition products of PPC contains ether, which might produce through condensation reaction of alcohol compounds. To retard this side reaction, graphene oxide is applied to coat commercial LiNi 0.5 Co 0.2 Mn 0.3 O 2 particles via a facile chemical approach. Compared with pristine cathode, the coated sample displays higher initial capacity, better cycle stability and lower interfacial resistance after cycled. After 300 cycles, the capacity retention is 69.2% at 0.3 C and the resistance is only 25 Ω after 180 cycles. This is due to the graphene layer facilitates the interfacial charge-transfer process and slows the cathode/ electrolyte interfacial side reaction. Consequently, the study illuminated the interface issues of PPC based solid-state lithium batteries.
K E Y W O R D Sall-solid-state lithium battery, graphene oxide, interface, LiNi 0.5 Co 0.2 Mn 0.3 O 2 , poly(propylene carbonate)
In this work, a novel core‐shell structure consisting of a porous graphite core, a nanosilicon filler layer, and a pitch coating carbon shell has been developed for lithium‐ion battery anode material. This structure was prepared by liquid‐phase milling and carbonization processes. Compared with other silicon (Si)‐based anode materials, this structure has a unique three‐dimensional conductive network consisting of conductive materials of conductive carbon, graphene, porous graphite, and carbon shell. The conductive network could effectively enhance the conductivity of the core‐shell structure. In addition, this structure was designed with moderate porous rate that provided nanosilicon appropriate expansion space. The coin cell test showed that this new material has a reversible capacity of 400 mA h g−1, retention of above 95% after 40 cycles, an initial columbic efficiency of 83.04%, and an average coulombic efficiency of above 99%. This novel material could have a great potential for future commercial application. The structure designed could be a possible solution for Si anode materials with low manufacturing cost and high performance.
Li
metal anodes possess the largest energy density among all anode
candidates, while dendrite growth is a huge barrier for its application.
Herein, carbon cloth modified with ZnO–CoO particles is synthesized
as a host for Li metal anodes (Li-ZnO–CoO/CC). During plating,
Li tends to first fill the inside space of the Li-ZnO–CoO/CC,
while in stripping, Li will be stripped from the surface. In addition,
the three-dimensional (3D) structure could enable an internal space
for Li deposition and alleviate Li volume expansion. As a result,
ZnO–CoO/CC has better lithiophilic properties and a lower nucleation
overpotential (1.2 mV), leading to over 600 h of stable Li plating/stripping
at 5 mA cm–2–1 mAh cm–2 for a voltage hysteresis of 15.5 mV. In addition, the NCM523||Li-ZnO–CoO/CC
cell exhibits a capacity retention of 92.4% at 0.3 C for 300 cycles.
This work creates a valid design of a double-lithiophilic spot carbon
cloth-based Li metal anode.
Interfacial side reaction mechanism between poly(propylene carbonate) solid polymer electrolyte (PPC‐SPE) and LiNi0.5Co0.2Mn0.3O2 cathode (c‐NCM) is investigated. Ni3+ and Co4+ species generated by electrochemical oxidization process can decompose poly(propylene carbonate) to aldehyde. To address this interface issue, a graphene interlayer is introduced to the LiNi0.5Co0.2Mn0.3O2 cathode surface via a facile method to improve cycle stability, rate capability and interfacial resistance. After 50 cycles at 0.3 C, the capacity retention of G@c‐NCM is 97.9 % and the resistance is less than 20 Ω, the improved electrochemical properties can be attributed to the graphene interlayer slows the side reaction, facilitates interfacial charge‐transfer process and stabilizes the cathode structure. These results demonstrate that modifying LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode surface with graphene interlayer is conducive to enhance the electrochemical performance of all‐solid‐state lithium batteries.
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