A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a ...A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell.The results show an increase of 1%initial capacity for the battery aged at 100%depth of discharge(DOD)and 45℃.Furthermore,large DODs or high temperatures accelerate the capacity increase.From the incremental capacity and differential voltage(IC-DV)analysis,we concluded that the increased capacity in a full cell originates from the graphite anode.Furthermore,graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs,thus in agreement with the full cell results.Post-mortem analysis results show that a larger DOD enlarges the graphite dspace and separates the graphite layer structure,facilitating the Li+diffusion,hence increasing the battery capacity.展开更多
A good cycling stability is a prerequisite for the application of metal-based materials in lithium-ion batteries(LIBs). However, an abnormal increase in capacity is often observed, which has rarely been focused on in ...A good cycling stability is a prerequisite for the application of metal-based materials in lithium-ion batteries(LIBs). However, an abnormal increase in capacity is often observed, which has rarely been focused on in many studies. In our SnSe-Mo-C composite anode, a high reversible capacity of 737.4 mAh g^(-1)remained after 5000 cycles at 5 A g^(-1)between 0.01 and 3.0 V versus Li/Li+. However, a continuous capacity increase occurred in the initial cycles, with 1086.9 mAh g^(-1)after 1000 cycles and 1216.9 mAh g^(-1)after 1500 cycles, respectively. Further studies revealed that the electrolyte decomposed at high potentials(2.5–3.0 V) and provided additional capacities. The cut-off voltage and electrolyte filling were controlled, which eliminated the impact of electrolyte decomposition, prevented rapid capacity decay, and provided a stable cycling performance for SnSe-Mo-C anodes in LIBs. This work shows that the composite anode is promising for lithium storage and the findings provide new insights into understanding and controlling the phenomenon of capacity increase with cycling in metal-based anode materials.展开更多
基金supported by a grant from the China Scholarship Council(202006370035 and 202006220024)supported by the National Natural Science Foundation of China(52107229)。
文摘A capacity increase is often observed in the early stage of Li-ion battery cycling.This study explores the phenomena involved in the capacity increase from the full cell,electrodes,and materials perspective through a combination of non-destructive diagnostic methods in a full cell and post-mortem analysis in a coin cell.The results show an increase of 1%initial capacity for the battery aged at 100%depth of discharge(DOD)and 45℃.Furthermore,large DODs or high temperatures accelerate the capacity increase.From the incremental capacity and differential voltage(IC-DV)analysis,we concluded that the increased capacity in a full cell originates from the graphite anode.Furthermore,graphite/Li coin cells show an increased capacity for larger DODs and a decreased capacity for lower DODs,thus in agreement with the full cell results.Post-mortem analysis results show that a larger DOD enlarges the graphite dspace and separates the graphite layer structure,facilitating the Li+diffusion,hence increasing the battery capacity.
基金supported by the National Natural Science Foundation of China(52071144,51831009,and 51621001)the Guangzhou Key Research and Development Program(202103040001)。
文摘A good cycling stability is a prerequisite for the application of metal-based materials in lithium-ion batteries(LIBs). However, an abnormal increase in capacity is often observed, which has rarely been focused on in many studies. In our SnSe-Mo-C composite anode, a high reversible capacity of 737.4 mAh g^(-1)remained after 5000 cycles at 5 A g^(-1)between 0.01 and 3.0 V versus Li/Li+. However, a continuous capacity increase occurred in the initial cycles, with 1086.9 mAh g^(-1)after 1000 cycles and 1216.9 mAh g^(-1)after 1500 cycles, respectively. Further studies revealed that the electrolyte decomposed at high potentials(2.5–3.0 V) and provided additional capacities. The cut-off voltage and electrolyte filling were controlled, which eliminated the impact of electrolyte decomposition, prevented rapid capacity decay, and provided a stable cycling performance for SnSe-Mo-C anodes in LIBs. This work shows that the composite anode is promising for lithium storage and the findings provide new insights into understanding and controlling the phenomenon of capacity increase with cycling in metal-based anode materials.
