There are plenty of issues need to be solved before the practi-cal application of Li-and Mn-rich cathodes,including the detrimental voltage decay and mediocre rate capability,*** doping can e ectively solve the above ...
详细信息
There are plenty of issues need to be solved before the practi-cal application of Li-and Mn-rich cathodes,including the detrimental voltage decay and mediocre rate capability,*** doping can e ectively solve the above problems,but cause the loss of *** introduction of appropriate defects can compensate the capacity loss;however,it will lead to structural mismatch and stress ***,a three-in-one method that combines cation–polyanion co-doping,defect construction,and stressengineering is *** co-doped Na^(+)/SO_(4)^(2-)can stabilize the layer framework and enhance the capacity and voltage *** induced defects would activate more reac-tion sites and promote the electrochemical ***,the unique alternately distributed defect bands and crystal bands structure can alleviate the stress accumulation caused by changes of cell parameters upon ***,the modified sample retains a capacity of 273 mAh g^(-1)with a high-capacity retention of 94.1%after 100 cycles at 0.2 C,and 152 mAh g^(-1)after 1000 cycles at 2 C,the corresponding voltage attenuation is less than 0.907 mV per cycle.
The problem of an eventual usefulness of defects and traps in solar cells land especially in implanted Si material) has been investigated since the 1980s. Usually in place of an increase, the efficiency actually dimin...
详细信息
The problem of an eventual usefulness of defects and traps in solar cells land especially in implanted Si material) has been investigated since the 1980s. Usually in place of an increase, the efficiency actually diminishes because of the nonradiative recombination on numerous defects. At the beginning of the 1990s a new approach was proposed. The fundamental difference concerns the thermodynamic aspects of devices: microelectronic and photovoltaic (PV) which differentiates a receiver from a generator. In the solar cell, there is an additional dimension, i.e. optoelectronic properties where the electronic behaviour (recombination) can be completed/modified by an optical activity (generation). PV characteristics depend simultaneously on optical (absorption, conversion) and electronic (carrier transport and collection) behaviour. We have analyzed theoretically and experimentally some possible modifications of the post-implantation defect activity on single-crystal Si in view of a very- and ultra-high PV conversion efficiency. The applied techniques can be classified as bandgap, defect and stress engineering. The results of the local crystalline modification have been compared with those obtained by spectral response. We show that an adequate implantation and annealing allow an important transformation of conversion, transport and collecting characteristics. (C) 1999 Elsevier Science B.V. All rights reserved.
暂无评论